I don’t know if this program was on anyone’s radar, but , “Paint 3D”, a free program perfectly exports fbx files from the 3d models you export out of it after allowing you to paint on the model with no errors. The only thing you have to do is that, after you export the fbx model and import it into the unreal engine, you just have to select all the parts of the fbx and increase the scale by like 500 and everything looks perfect. I tested it on multiple models and even ones provided by its central database of models to use and it worked flawlessly. Here is a screenshot after importing into the unreal engine. I just took the model from “Remix 3d”, which is the database you can browse in the program itself.
Here is another example of flawless export. I downloaded from there database and it took me just a minute to import this. I hope this helps anyone or if anyone can give tips.