Pycraft has 3 accounts mode. The mojang account mode(microsoft accounts support coming soon),
cracked mode and ely_by login system. For the majority of the people who don't know what that is, it is an alternative minecraft service used by Tlauncher as well, only that their security is better. For this mode, you need to create an account at https://ely.by (2 factor authentication not yet supported), and then enter your username and password and start. Supported for all modes, vanilla, forge and fabric.
Ely_by skins are not viewable on all servers, only in singleplayer mode and those servers which
use it's services. However to view your skin on all servers you can use a client side mod, https://www.curseforge.com/minecraft/mc-mods/customskinloader/ , usage instructions are given on the page. Officially supported till 1.16.5 but there are release versions for the mod for 1.17 in the files section. Just run this mod one time, close minecraft, go to .minecraft/CustomSkinLoader/CustomSkinLoader.json, open it with any text editor
from the webiste : "- Q: How can I modify configurations of CustomSkinLoader?
A: The config file is .minecraft/CustomSkinLoader/CustomSkinLoader.json . Unfortunately, there is no way to modify the CustomSkinLoader configuration file in the game currently, so you need to manually modify it by using a code editor (e.g. VSCode). However, we have a website to modify the configuration file online, you only need to import and modify your current configuration file."
This mod supports: LittleSkin, BlessingSkin, Elyby, SkinMe, GlitchlessGames skins. Since ely_by is the most popular choice, you can go ahead with this mod.
And yea this mod has no impact on physical resources, like ram and cpu(I used it a lot of times).