It is easy to redesign a polygon model.
The problem is mesh destruction that occurs at import.
The solution is UV smoothing, correcting the orientation of vertices and face normals, binding the model to bones, etc.
If it does not solve it, leave it.
If we can bind all the bones necessary for the body, 90% will be solved but ... pactool is impossible because there is a limit on the number of bones
Well it is my own words.