I just uploaded mine with @zlaggaming and @catsyrup5000 help. It wasn't working at first, but this time, I uploaded a random image from my computer as the preview, I guess it registered the one I was trying to use as too NSFW.
actually the mod's nsfw game model seems to be made with unreal cutout materials.
you could recreate something similar in unity and more if you manage to rip the avatar above then
an nsfw version is not impossible