yeah, this is a very common mistake and it’s like the fifth post with the same problem in the last week.
all I will say is DO NOT save animations from AnimationPlayer, I don’t know why people keep doing that.
you need to export your animations from blender into a one glb file containing a bunch of them, then set it to AnimationLibrary, and then import it in the AnimationPlayer.
also, your character is in T-POSE, but the animation is NOT in t-pose, as it is not from mixamo but probably from sketchfab or some other site.
do not use something like that which is a single animation mixing all into one, it won’t work in godot. you need to open the file in blender and break them into different actions.
also it doesn’t have a root bone, which is essential to make the character move correctly with mixamo or other motion capture animations.
take a look at this post:
which has the exact same problem and a solution.
it also references another post which is the workflow I use for retargeting animations in godot, and from mixamo: