(UPDATE)
If you wan't to help, im sharing my source files (v41) to make it easier.

Here's what up:

- i had trouble making fingers and hands look okay when animated, so I got rid of fingers bone weight alltogether for now
- some areas need weight paint adjusting to look good, but to not clip through clothes as much
- shoulder bones are slightly displaced compared to original, so in game they don't look as wide. This is intended.
- vanilla textures aren't symmetrical, so I compensated that by shifting UVs, and then started drawing my textures, so the're slightly off center as well.
- some glasses and accessories do not fit well, as I tried do make realistic face proportions while keeping everything else the same

I'm sharing my blend files and all textures used;
https://drive.google.com/file/d/16Q6UpL0V20J-d8zPGHygKEtqajbxU6cM/view?usp=sharing

and blender FBX export settings:
https://i.imgur.com/cVnx5qb.png

Yes, it's terrible in many ways, cause its just the default model subdivided once, then sculpted.