You can now enjoy custom Skyboxes in Fabric on 1.18.1 using this cool mod and resource packs. View full article to see how!
Video Source: https://youtu.be/ADgnha8tvgY
To get custom skyboxes up and running on Fabric 1.18.1 you will need the following:-
Fabric SkyBoxes Mod - From Here
Then you will need the custom converted resource packs. Join the mod author's Discord page Here
Then click on the Converted Skypacks section on the left
You can then find the packs on here
Go to your Minecraft directory (C:\Users\User\AppData\Roaming\.minecraft)
Then find a folder called 'resourcepacks' if you don't have this, then create it.
Place your skybox packs inside here
You can only use one pack at a time. The pack at the top of the Selected list will also be the main pack that is used.
You can also get a converter that will convert OptiFine resourcepacks for the FabricSkyboxes mod.
Get it from Here (You can get the Windows version with a GUI)