[Bug] Can't handle 5120 x 1440 display

[liljom]

I have a 5120 by 1440 resolution screen, that works well with other distros.
When I first tried to use it with Pop_OS 24.04 alpha2, it recognized the screen nicely, but set a 4K resolution. In the display settings it shows the option of max resolution (5120x1440), but it doesn't change when I select it. It acts like it does, offering the Keep or Revert options, but the actual resolution is stil 4K.
So I tried 3440x1080, just to get a better ratio, but acts the same: thinks it did it, but haven't.
I got a Ryzen 7 PRO 8840U w/ Radeon 780M.

[liljom]

Just tested with the external screen at home, which was used during PopOS install. 4K screen, and can't change the resolution here either.
When I use for example cosmic-randr mode --test DP-2 1920 1200 it scales down the desktop to the top-left corner, and the rest of the screen is black.
But then, when I click the 1920*1200 resolution in the settings, it is actually applied properly. I can even change it back to 4K from settings (no other option works), but after that it becomes unresponsive again

[liljom]

Update: managed to set the work screen resolution to 5120*1440 by editing ~/.local/state/cosmic-com/outputs.ron and restarting the laptop