Hi, it seems your BiomeColors mixin is causing a crash with Sodium Reforged, looks like some code was removed from the Fabric version since Forge didn't have Sodium. Not sure whose end this is on.

https://github.com/paulevsGitch/BetterEnd/blob/f6d46844270a3d0696243ed826a67500b7b67ad4/src/main/java/ru/betterend/mixin/client/BiomeColorsMixin.java

https://pastebin.com/Q4SnC471

I ported that portion of code to work with Sodium Reforged because I was curious if it was on BetterEnd's issue and it sadly didn't fix it.

Can confirm it crashes... unplayable game withotu sodium :(