diff --git a/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/schema/charts/heatmap.ts b/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/schema/charts/heatmap.ts
index a914bf139ab9a..fedd8bd007d04 100644
--- a/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/schema/charts/heatmap.ts
+++ b/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/schema/charts/heatmap.ts
@@ -64,7 +64,7 @@ const heatmapSharedStateSchema = {
   ),
   ...sharedPanelInfoSchema,
   ...layerSettingsSchema,
-  axis: schema.maybe(
+  axes: schema.maybe(
     schema.object(
       {
         x: schema.maybe(
diff --git a/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/schema/charts/tagcloud.test.ts b/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/schema/charts/tagcloud.test.ts
index 5b85ba07a3036..58451a12bde5a 100644
--- a/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/schema/charts/tagcloud.test.ts
+++ b/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/schema/charts/tagcloud.test.ts
@@ -91,7 +91,7 @@ describe('Tagcloud Schema', () => {
                 color: { type: 'from_palette', palette: 'default', index: 0 },
               },
             ],
-            unassignedColor: { type: 'color_code', value: '#cccccc' },
+            unassigned: { type: 'color_code', value: '#cccccc' },
           },
         },
       };
diff --git a/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/schema/color.test.ts b/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/schema/color.test.ts
index ed4d12f4b88ba..d1aa38e3428e8 100644
--- a/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/schema/color.test.ts
+++ b/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/schema/color.test.ts
@@ -9,7 +9,12 @@
 
 import { freeze, produce } from 'immer';
 
-import type { ColorByValueStep, ColorByValueType, ColorMappingType } from './color';
+import type {
+  ColorByValueStep,
+  ColorByValueType,
+  ColorMappingCategoricalType,
+  ColorMappingType,
+} from './color';
 import { allColoringTypeSchema, colorByValueStepsSchema } from './color';
 
 describe('Color Schema', () => {
@@ -238,7 +243,7 @@ describe('Color Schema', () => {
             color: { type: 'color_code', value: 'red' },
           },
         ],
-        unassignedColor: { type: 'color_code', value: 'green' },
+        unassigned: { type: 'color_code', value: 'green' },
       };
 
       const validated = allColoringTypeSchema.validate(input);
@@ -271,7 +276,7 @@ describe('Color Schema', () => {
             color: { type: 'from_palette', palette: 'default', index: 0 },
           },
         ],
-        unassignedColor: { type: 'color_code', value: 'green' },
+        unassigned: { type: 'color_code', value: 'green' },
       };
 
       const validated = allColoringTypeSchema.validate(input);
@@ -354,7 +359,7 @@ describe('Color Schema', () => {
             palette: 'default',
           },
         ],
-        unassignedColor: { type: 'color_code', value: 'green' },
+        unassigned: { type: 'color_code', value: 'green' },
       };
 
       const validated = allColoringTypeSchema.validate(input);
@@ -376,25 +381,15 @@ describe('Color Schema', () => {
       it('throws on invalid mode in color mapping', () => {
         const input = {
           palette: 'kibana_palette',
+          // @ts-expect-error
           mode: 'invalid',
-          colorMapping: {
-            values: ['value1'],
-          },
-          otherColors: {},
-        };
-
-        expect(() => allColoringTypeSchema.validate(input)).toThrow();
-      });
-
-      it('throws on empty values array in categorical mapping', () => {
-        const input = {
-          palette: 'kibana_palette',
-          mode: 'categorical',
-          colorMapping: {
-            values: [],
-          },
-          otherColors: {},
-        };
+          mapping: [
+            {
+              values: ['value1'],
+              color: { type: 'color_code', value: '#FF00FF' },
+            },
+          ],
+        } satisfies ColorMappingCategoricalType;
 
         expect(() => allColoringTypeSchema.validate(input)).toThrow();
       });
diff --git a/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/schema/color.ts b/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/schema/color.ts
index 0b0e320658afd..4290fffbbfc81 100644
--- a/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/schema/color.ts
+++ b/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/schema/color.ts
@@ -231,6 +231,10 @@ const colorCodeSchema = schema.object(
 
 const colorDefSchema = schema.oneOf([colorFromPaletteSchema, colorCodeSchema]);
 
+const unassignedColorSchema = schema.oneOf([colorFromPaletteSchema, colorCodeSchema], {
+  meta: { description: 'The color to use for unassigned values.', id: 'unassignedColorSchema' },
+});
+
 const categoricalColorMappingSchema = schema.object(
   {
     mode: schema.literal('categorical'),
@@ -244,7 +248,7 @@ const categoricalColorMappingSchema = schema.object(
       }),
       { maxSize: 1000 }
     ),
-    unassignedColor: schema.maybe(colorDefSchema),
+    unassigned: schema.maybe(unassignedColorSchema),
   },
   { meta: { id: 'categoricalColorMapping', title: 'Categorical Color Mapping' } }
 );
@@ -269,7 +273,7 @@ const gradientColorMappingSchema = schema.object(
       )
     ),
     gradient: schema.maybe(schema.arrayOf(colorDefSchema, { maxSize: 3 })),
-    unassignedColor: schema.maybe(colorDefSchema),
+    unassigned: schema.maybe(unassignedColorSchema),
   },
   { meta: { id: 'gradientColorMapping', title: 'Gradient Color Mapping' } }
 );
@@ -305,6 +309,7 @@ export type ColorMappingCategoricalType = TypeOf<typeof categoricalColorMappingS
 export type ColorMappingGradientType = TypeOf<typeof gradientColorMappingSchema>;
 export type ColorMappingColorDefType = TypeOf<typeof colorDefSchema>;
 export type AllColoringTypes = TypeOf<typeof allColoringTypeSchema>;
+export type UnassignedColorType = TypeOf<typeof unassignedColorSchema>;
 /**
  * Schema for where to apply the color (to value or background).
  */
diff --git a/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/schema/shared.ts b/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/schema/shared.ts
index febc2b55d2cbf..7d989b4352409 100644
--- a/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/schema/shared.ts
+++ b/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/schema/shared.ts
@@ -153,9 +153,7 @@ const layerSettingsSchemaWrapped = schema.object(layerSettingsSchema);
 export type LayerSettingsSchema = TypeOf<typeof layerSettingsSchemaWrapped>;
 
 export const axisTitleSchemaProps = {
-  value: schema.maybe(
-    schema.string({ defaultValue: '', meta: { description: 'Axis title text' } })
-  ),
+  text: schema.maybe(schema.string({ defaultValue: '', meta: { description: 'Axis title text' } })),
   visible: schema.maybe(schema.boolean({ meta: { description: 'Show the title' } })),
 };
 
diff --git a/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/transforms/charts/heatmap/from_api.ts b/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/transforms/charts/heatmap/from_api.ts
index eb82e2d958b74..0692d69d22c7d 100644
--- a/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/transforms/charts/heatmap/from_api.ts
+++ b/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/transforms/charts/heatmap/from_api.ts
@@ -53,7 +53,7 @@ function buildVisualizationState(config: HeatmapState): HeatmapVisualizationStat
   const layer = config;
   const valueAccessor = getAccessorName('value');
   const basePalette = layer.metric.color && fromColorByValueAPIToLensState(layer.metric.color);
-  const xAxisLabelRotation = getRotationFromOrientation(layer.axis?.x?.labels?.orientation);
+  const xAxisLabelRotation = getRotationFromOrientation(layer.axes?.x?.labels?.orientation);
 
   return {
     layerId: DEFAULT_LAYER_ID,
@@ -65,16 +65,16 @@ function buildVisualizationState(config: HeatmapState): HeatmapVisualizationStat
     gridConfig: {
       type: HEATMAP_GRID_NAME,
       isCellLabelVisible: layer.cells?.labels?.visible ?? false,
-      isXAxisLabelVisible: layer.axis?.x?.labels?.visible ?? true,
-      isXAxisTitleVisible: layer.axis?.x?.title?.visible ?? false,
-      isYAxisLabelVisible: layer.axis?.y?.labels?.visible ?? true,
-      isYAxisTitleVisible: layer.axis?.y?.title?.visible ?? false,
+      isXAxisLabelVisible: layer.axes?.x?.labels?.visible ?? true,
+      isXAxisTitleVisible: layer.axes?.x?.title?.visible ?? false,
+      isYAxisLabelVisible: layer.axes?.y?.labels?.visible ?? true,
+      isYAxisTitleVisible: layer.axes?.y?.title?.visible ?? false,
       ...stripUndefined<HeatmapGridConfigResult>({
-        xTitle: layer.axis?.x?.title?.value,
-        yTitle: layer.axis?.y?.title?.value,
+        xTitle: layer.axes?.x?.title?.text,
+        yTitle: layer.axes?.y?.title?.text,
         xAxisLabelRotation,
-        xSortPredicate: layer.axis?.x?.sort,
-        ySortPredicate: layer.axis?.y?.sort,
+        xSortPredicate: layer.axes?.x?.sort,
+        ySortPredicate: layer.axes?.y?.sort,
       }),
     },
     legend: {
diff --git a/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/transforms/charts/heatmap/to_api.ts b/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/transforms/charts/heatmap/to_api.ts
index ee5c904e372de..fde2aeaeb027b 100644
--- a/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/transforms/charts/heatmap/to_api.ts
+++ b/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/transforms/charts/heatmap/to_api.ts
@@ -53,7 +53,7 @@ function getOrientationFromRotation(rotation: number): 'angled' | 'vertical' | '
 
 function getGridConfigProps(
   gridConfig: HeatmapVisualizationState['gridConfig']
-): HeatmapState['axis'] {
+): HeatmapState['axes'] {
   return {
     x: {
       labels: {
@@ -63,7 +63,7 @@ function getGridConfigProps(
         }),
       },
       title: {
-        value: gridConfig.xTitle,
+        text: gridConfig.xTitle,
         visible: gridConfig.isXAxisTitleVisible,
       },
       ...(gridConfig.xSortPredicate ? { sort: gridConfig.xSortPredicate } : {}),
@@ -71,7 +71,7 @@ function getGridConfigProps(
     y: {
       labels: { visible: gridConfig.isYAxisLabelVisible },
       title: {
-        value: gridConfig.yTitle,
+        text: gridConfig.yTitle,
         visible: gridConfig.isYAxisTitleVisible,
       },
       ...(gridConfig.ySortPredicate ? { sort: gridConfig.ySortPredicate } : {}),
@@ -96,7 +96,7 @@ function reverseBuildVisualizationState(
     ...generateApiLayer(layer),
     type: HEATMAP_NAME,
     legend: getLegendProps(visualization.legend),
-    axis: getGridConfigProps(visualization.gridConfig),
+    axes: getGridConfigProps(visualization.gridConfig),
     cells: {
       labels: { visible: visualization.gridConfig.isCellLabelVisible },
     },
diff --git a/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/transforms/charts/xy/chart.ts b/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/transforms/charts/xy/chart.ts
index 6b10a2c16c6cf..03fc2ca2df2f0 100644
--- a/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/transforms/charts/xy/chart.ts
+++ b/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/transforms/charts/xy/chart.ts
@@ -127,9 +127,9 @@ function convertAxisSettingsToStateFormat(
           yLeft: orientationDictionary[axis?.left?.labels?.orientation ?? 'horizontal'],
           yRight: orientationDictionary[axis?.right?.labels?.orientation ?? 'horizontal'],
         };
-  const xTitle = axis?.x?.title?.value;
-  const yTitle = axis?.left?.title?.value;
-  const yRightTitle = axis?.right?.title?.value;
+  const xTitle = axis?.x?.title?.text;
+  const yTitle = axis?.left?.title?.text;
+  const yRightTitle = axis?.right?.title?.text;
   const yLeftScale = axis?.left?.scale;
   const yRightScale = axis?.right?.scale;
   return stripUndefined({
@@ -259,13 +259,28 @@ function convertXExtent(extent: AxisExtentConfig | undefined): {
   return {};
 }
 
+/**
+ * Returns the first map key whose value strictly equals the provided value.
+ */
+function findKeyByValue<T extends Record<string, unknown>>(
+  map: T,
+  value: unknown
+): Extract<keyof T, string> | undefined {
+  return Object.keys(map).find((key): key is Extract<keyof T, string> => map[key] === value);
+}
+
 function convertAxisSettingsToAPIFormat(
   config: XYPersistedState,
   layers: Record<string, DataSourceStateLayer>
 ): Pick<XYState, 'axis'> | {} {
   const axis: EditableAxisType = {};
 
-  let xAxisScale: string | undefined;
+  const { labelsOrientation } = config;
+  const xLabelsOrientation = findKeyByValue(orientationDictionary, labelsOrientation?.x);
+  const yLeftLabelsOrientation = findKeyByValue(orientationDictionary, labelsOrientation?.yLeft);
+  const yRightLabelsOrientation = findKeyByValue(orientationDictionary, labelsOrientation?.yRight);
+
+  let xAxisScale: XAxisType['scale'];
   const firstLayer = config.layers[0];
   const dataSourceLayer = layers[firstLayer.layerId];
   if (isTextBasedLayer(dataSourceLayer) && isLensStateDataLayer(firstLayer)) {
@@ -283,7 +298,7 @@ function convertAxisSettingsToAPIFormat(
     title:
       config.xTitle || config.axisTitlesVisibilitySettings?.x != null
         ? stripUndefined({
-            value: config.xTitle,
+            text: config.xTitle,
             visible:
               config.axisTitlesVisibilitySettings?.x != null
                 ? config.axisTitlesVisibilitySettings.x
@@ -300,17 +315,9 @@ function convertAxisSettingsToAPIFormat(
         ? { visible: config.gridlinesVisibilitySettings.x }
         : undefined,
     ...convertXExtent(config.xExtent),
-    ...(config.labelsOrientation?.x != null
-      ? {
-          labels: {
-            orientation: Object.entries(orientationDictionary).find(
-              ([_, value]) => value === config.labelsOrientation?.x
-            )?.[0] as 'horizontal' | 'vertical' | 'angled' | undefined,
-          },
-        }
-      : {}),
+    labels: xLabelsOrientation ? { orientation: xLabelsOrientation } : undefined,
     scale: xAxisScale,
-  });
+  } satisfies XAxisType);
   if (Object.keys(xAxis).length) {
     axis.x = xAxis;
   }
@@ -319,7 +326,7 @@ function convertAxisSettingsToAPIFormat(
     title:
       config.yTitle || config.axisTitlesVisibilitySettings?.yLeft != null
         ? stripUndefined({
-            value: config.yTitle,
+            text: config.yTitle,
             visible:
               config.axisTitlesVisibilitySettings?.yLeft != null
                 ? config.axisTitlesVisibilitySettings.yLeft
@@ -336,16 +343,8 @@ function convertAxisSettingsToAPIFormat(
         ? { visible: config.gridlinesVisibilitySettings.yLeft }
         : undefined,
     ...convertExtendsToAPIFormat(config.yLeftExtent),
-    ...(config.labelsOrientation?.yLeft != null
-      ? {
-          labels: {
-            orientation: Object.entries(orientationDictionary).find(
-              ([_, value]) => value === config.labelsOrientation?.yLeft
-            )?.[0] as 'horizontal' | 'vertical' | 'angled' | undefined,
-          },
-        }
-      : {}),
-  });
+    labels: yLeftLabelsOrientation ? { orientation: yLeftLabelsOrientation } : undefined,
+  } satisfies YAxisType);
   if (Object.keys(leftAxis).length) {
     axis.left = leftAxis;
   }
@@ -354,7 +353,7 @@ function convertAxisSettingsToAPIFormat(
     title:
       config.yRightTitle || config.axisTitlesVisibilitySettings?.yRight != null
         ? stripUndefined({
-            value: config.yRightTitle,
+            text: config.yRightTitle,
             visible:
               config.axisTitlesVisibilitySettings?.yRight != null
                 ? config.axisTitlesVisibilitySettings.yRight
@@ -371,15 +370,7 @@ function convertAxisSettingsToAPIFormat(
         ? { visible: config.gridlinesVisibilitySettings.yRight }
         : undefined,
     ...convertExtendsToAPIFormat(config.yRightExtent),
-    ...(config.labelsOrientation?.yRight != null
-      ? {
-          labels: {
-            orientation: Object.entries(orientationDictionary).find(
-              ([_, value]) => value === config.labelsOrientation?.yRight
-            )?.[0] as 'horizontal' | 'vertical' | 'angled' | undefined,
-          },
-        }
-      : {}),
+    labels: yRightLabelsOrientation ? { orientation: yRightLabelsOrientation } : undefined,
   });
 
   if (Object.keys(rightAxis).length) {
diff --git a/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/transforms/coloring/coloring.test.ts b/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/transforms/coloring/coloring.test.ts
index fae59622b34b9..c74a77a344061 100644
--- a/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/transforms/coloring/coloring.test.ts
+++ b/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/transforms/coloring/coloring.test.ts
@@ -828,7 +828,7 @@ describe('Color util transforms', () => {
             color: { type: 'color_code', value: '#ff0000' },
           },
         ],
-        unassignedColor: { type: 'color_code', value: '#00ff00' },
+        unassigned: { type: 'color_code', value: '#00ff00' },
       };
 
       const lensState = fromColorMappingAPIToLensState(originalColorMapping);
@@ -884,7 +884,7 @@ describe('Color util transforms', () => {
           { type: 'from_palette', index: 2, palette: 'no_default' },
         ],
         sort: 'asc',
-        unassignedColor: { type: 'from_palette', palette: SEMANTIC_PALETTE, index: 2 },
+        unassigned: { type: 'from_palette', palette: SEMANTIC_PALETTE, index: 2 },
       };
 
       const lensState = fromColorMappingAPIToLensState(originalColorMapping);
diff --git a/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/transforms/coloring/coloring.ts b/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/transforms/coloring/coloring.ts
index ad0ad89b3b23a..ba18849b2a9fb 100644
--- a/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/transforms/coloring/coloring.ts
+++ b/src/platform/packages/shared/kbn-lens-embeddable-utils/config_builder/transforms/coloring/coloring.ts
@@ -14,9 +14,12 @@ import type {
   ColorByValueAbsolute,
   ColorByValueStep,
   ColorByValueType,
+  ColorMappingCategoricalType,
   ColorMappingColorDefType,
+  ColorMappingGradientType,
   ColorMappingType,
   StaticColorType,
+  UnassignedColorType,
 } from '../../schema/color';
 import type { SerializableValueType } from '../../schema/serializedValue';
 
@@ -274,12 +277,11 @@ function isLensStateCategoricalConfigColorMapping(
 
 function fromUnassignedColorLensStateToAPI(
   color: ColorMapping.CategoricalColor | ColorMapping.ColorCode | ColorMapping.LoopColor | undefined
-): { unassignedColor: Extract<ColorMappingColorDefType, { type: 'color_code' }> } | {} {
+): UnassignedColorType | undefined {
   if (!color || color.type === 'loop') {
-    return {};
+    return undefined;
   }
-  const unassignedColor = fromColorLensStateToAPI(color);
-  return { unassignedColor };
+  return fromColorLensStateToAPI(color);
 }
 
 export function fromColorMappingLensStateToAPI(
@@ -291,15 +293,13 @@ export function fromColorMappingLensStateToAPI(
       mode: 'categorical',
       palette: `${LEGACY_PALETTE_PREFIX}${legacyPalette.name}`,
       mapping: [],
-    };
+    } satisfies ColorMappingCategoricalType;
   }
   if (!colorMapping) {
     return;
   }
 
-  const unassignedColor = fromUnassignedColorLensStateToAPI(
-    colorMapping.specialAssignments[0]?.color
-  );
+  const unassigned = fromUnassignedColorLensStateToAPI(colorMapping.specialAssignments[0]?.color);
   if (isLensStateCategoricalConfigColorMapping(colorMapping)) {
     return {
       mode: 'categorical',
@@ -310,8 +310,8 @@ export function fromColorMappingLensStateToAPI(
           color: fromColorLensStateToAPI(color),
         };
       }),
-      ...unassignedColor,
-    };
+      ...(unassigned ? { unassigned } : {}),
+    } satisfies ColorMappingCategoricalType;
   }
 
   // because of early return above, we know it is a gradient at this point so casting is safe
@@ -328,8 +328,8 @@ export function fromColorMappingLensStateToAPI(
     }),
     sort: (colorMapping.colorMode as ColorMapping.GradientColorMode).sort,
     gradient: colorMode.steps.map((color) => fromColorLensStateToAPI(color)),
-    ...unassignedColor,
-  };
+    ...(unassigned ? { unassigned } : {}),
+  } satisfies ColorMappingGradientType;
 }
 
 function fromColorDefAPIToLensState(
@@ -411,8 +411,8 @@ export function fromColorMappingAPIToLensState(
           type: 'other',
         },
       ],
-      color: colorMapping.unassignedColor
-        ? fromColorDefAPIToLensState(colorMapping.unassignedColor)
+      color: colorMapping.unassigned
+        ? fromColorDefAPIToLensState(colorMapping.unassigned)
         : { type: 'loop' },
       touched: false,
     },