Thanks to Arx Libertalis and Reshade bringing new life to classics, I though I would add to the mix by posting my work.
Step one was to use photo restoration BRSGAN (Well step one was making sure that arx would work with HD textures)
Step two leave my PC at running overnight to add amazing detail using the FLUX AI model on over 1500 textures.
I removed 99% of any textures causing issues, I am not sure how transparency is handled in FLUX but it appears to be tied to BMP and pixel for pixel so those images could not be up scaled or recreated.
If you have any suggestions for other games that would support this I am up for it.
I am trying to find the AVI codec for the old thief videos to up sample them (BRSGAN only FLUX would take weeks and not be contestant)