I've seen one other post talking about this issue and it was a few months old and has not been resolved.

I have the same issue

I looked through the files, the pale wolf textures are missing.
(Edit: Pale is the OG wolf texture, so I think the mod is looking for it in the game files. But it's not called pale until 1.20.5)

Please fix.

I have the same issue,VariantID: "moremobvariants:pale",

Maybe you can try try this first：https://www.curseforge.com/minecraft/texture-packs/more-mob-variants-fix