I did buyed it! I tried the demo on UE5 and it work, but I wanted to use it on Unity or Godot, the fbx included doesn't work as expected because the dimensions are different and they appear all in the "center". I ended up digging a little bit on Blender and exported my own FBX using some values I saw on a youtube video for Unity and now I can use them! So now I'm only stuck on the animations because they all move the root of the character so I need to remove the root movement for all animations, but "its fine" I guess !
I'm wondering if you are open for comissions btw