The once with the problem are the .nif "Gamebryo File Format, Version 20.3.1.2" neither of those apps or plugins Nifspoke,3ds max,blender,noesis can open.
PS: I do not have a ton of knowledge about editing the file version and if you try to say for example: use hex to edit the header with "this file" , you are not helping me at all to be honest!
Thanks for reading atleast though!.
Edit: I did manage to convert them but 3ds max wont import only noesis can export but with unwelded parts
