Unfortunately, I don't use Unreal, but if you just need a Tpose I can add that for you, the animations were exported from Unity, so I don't know if I could give you a source file, but other than the Tpose, I don't know how much help I'll be with Unreal as I don't know much on how the Animation System works, but feel free to ask me if you think I might be able to help.
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Hello, I also purchased this asset and tried to use it in the UE engine.
I attempted to directly import the FBX file into UE5, but it gave an error. Here's the error message: Mesh contains Root bone as root but animation doesn't contain the root track.
Based on the prompt, I tried changing the name of the root skeleton, but then I encountered another error: Could not create a valid skeleton from the import data that matches the given Skeletal Mesh. Check the bone names of both the Skeletal Mesh for this AnimSet and the animation data you are trying to import.
Can you tell me how you got the FBX to work properly?
I found these things on the errors, I don't really understand Unreal, so I hope this can help you.
https://forums.unrealengine.com/t/importing-animated-fxb-always-fails/22729