The workflow, start to finish, passing a Mixamo animation between models. I'll explain the concepts behind what you're doing so you can make your own universally compatible animations to pass between your models.

I take some liberties in the explanation, but my intent is to make it easier to understand, so you can troubleshoot issues that come up on your own, and can more easily identify where you may have gone wrong.

Godot 4.1 Stable
Blender 3.6.2