I don’t think it’s the drivers as disabling the hd textures fixes it. It’s far more likely the game developers didn’t optimise for Ampere at all. Since the game is a console port, it was fully optimised for the consoles and those carried over to AMD GPUs on PC.
The VRAM allocation on nvidia cards is completely broken and they need to patch it ASAP on priority. Those on high-end GPUs like the 3080 and above can brute force through that messed-up allocation with the pack disabled but users with the 3070 and below report low res textures and stuttering even with the pack disabled at 1440p. On the other hand, there are zero complaints from the mid-range AMD users in the long thread over on the Ubisoft forums. This is also clear when you see FC6 run on any RDNA 2 GPU. The game uses much more VRAM on the AMD cards relative to nvidia and does not stutter or show any issues with textures. The 6700XT actually provides a smoother experience than the 3080 Ti at 1440p, albeit at a lower frame rate simply because the game uses more of the 12GB VRAM on the former and there is no stuttering.
If they do not fix this allocation in a patch, it’s clear this is a deliberate crippling of nvidia cards in this game. Nvidia will never release a 16GB flagship card based on their past track record and the game developers should have developed a lite version of the texture pack with 10GB of VRAM requirements like they did in Watch Dogs Legion which was nvidia sponsored. At the moment, it’s either enjoy detailed textures on an AMD card or PS3 era textures on Nvidia.