The problem with Doom is that there's no actual PBR enviroment to make the most of those materials, only some sporadic dynamic lights can show how textures with those maps looks like in game. I used this to start a project for Doom that adds the required maps for pbr to all the vanilla lowres textures in Doom.
Hi there, recently the source port for Doom called GZDoom added support for pbr materials, and with a very handy feature that allows you to place the ao/metallic/roughness/normal map in a specific folder structure to make materials automatically.
