After troubleshooting every possible issue to try to get rid of the black textures, I have come to the conclusion that newer AMD cards like mine (RX5700 XT) dont like this game.
I installed it on my 10 year old amd laptop, which is the system I used to play the game on back in the day, and the issue doesnt exist there. I would play it on that but the HDD in that laptop is pretty much toast and can barely run rohan on it anymore. but at least the textures worked xD.
I then transferred the files from the laptop to my pc and the issue was still there so whatever, im done bothering with this lol. back to modding my skyrim/fallout 4 games which both run at 100+fps at 4k lol.