NVidia RTX worlds now failing

Having downloaded and tried out some RTX worlds, I then downloaded NVidia's standalone texture pack. Notably, some textures were always misconfigured (grass was LD and smooth plastic looking). Attempting to fix this, I disabled the official pack and downloaded tokomiki games texture pack. While the problems were now shuffled, some textures were still incorrect. After loading an official RTX world, I noticed several light sources were now failing. One fish tank illuminator in Light And Shadow turned off as I approached it. I disabled the texture pack to try and remedy the problem, but now even official RTX worlds are loading without RTX.