Fixing the texture/ quality of visibility issue for a 3D scanned file

I have a 3D-scanned file of a manufacturing hall with a couple of machines. When I'm loading the file into Blender or Unity, I'm losing a lot of textures, therefore I can't have a proper 3D image. The file I have contains obj, mtl, and some images. I will attach below how the 3D image is supposed to be and how it is now.