So I got a kitbash3d model (post-apocalypse) with a humble-bundle I bought awhile back (post apocalypse).

My system:
NVIDIA GeForce RTX 2070
AMD Ryzen 7 2700x
x470 Asus Rog Strix Motherboard
16 gb ddr 4 2666 ram

When I try to load the obj file (832mb), I get "not enough memory".
when I try to load the fbx file, it gets stuck on "dump trimesh" for a long time, and then when it finally loads, I get no textures.  Everything is gray.
I have an mtl file in the folder.  I also have a folder full of textures.  I could apply them manually, but am not sure how:

3dxchange has options for: diffuse, opacity, bump, specular, glow, reflection and blend.
In the texture folders, I have different textures labeled for different parts, and multiple files, including:  diffuse, disp, gloss (or glossiness), bump, normal, height, spec (or specular).

Some textures are self-explanatory:  diffuse, bump and specular are in both groups.  But where would the disp, gloss, normal, and height go?  And what would go in opacity, glow, reflection and blend?

It would be cool if I could just load the mtl file somehow and just have all the textures attach.  When looked at in 3dviewer, most of the textures seem okay.  However, if I could just figure out how to apply textures manually, that would help.

Any advice here would be appreciated.
Thank you in advance.