I don't know why but undervolting my GPU has reduced the stutters.

[Dysphunc]

Unfortunately I don't have any before footage but on my 5600X/4070/B450 system this was still chugging. Every room I entered would be a big stutter or entering combat would cause stutters too. But after undervolting I noticed it run WORSE for me playing in DX11, so I swapped it back to DX12 to use FG (as FG causes my 4070 to heat up - thanks Australian heat) and the game stopped stuttering. I turned off FG just to check but the stuttering was 90% gone. One little blip every few mins now, much less cope involved in playing now. I hit record and I captured 1, well 2 in 1 second stutter. You can see it's still horribly optimised as the framerate wildly fluctuates from room to room but the stuttering is bearable now.

Maybe this is a single case and no one else can repeat it, maybe it helps some people...

Link should be live shortly.
https://youtu.be/MUk3KP_f-KI