So, I'm not sure if this mod is solely responsible for this, or if it's an incompatibility, or what, but after several hours of doing a binary search through my mod list for the culprit of this issue, this mod turned out the be the one causing this.

Whenever I go to the world map screen with this mod enabled, whether it's starting a new game or in the middle of an ongoing one, I get a whole bunch of errors in the log along these lines:
And this causes all the textures for the map screen to vanish, aside from those for the various site and caravan icons.
This usually also results in the normal game screen losing all its textures as well, resulting in it being just black with text on it where text is normally displayed regardless.

The only mods I have installed that I could see being the cause of incompatibility with this one are Fortification Industrial: Citadel or Steve's Walls Continued.

I do hope this gets fixed soon. I really like this mod's extra doors and walls, but (based on nothing but my wild conjecture) I believe the incompatibility, if actually the case, may stem from the wall-blending system for the ornate and secure doors not knowing what to do with the textures of wall types or possibly materials added by other mods.