It’s overheating, plain and simple. And if you’re not running something like MSI Afterburner, you won’t notice it. I already posted a similar issue but in my case with EVGA RTX 3080 FTW3 Ultra.
The “solution” in my case was - and I can’t stress this enough - LOCK the damn game to 60 fps from the settings. My temps dropped drastically when I locked it to 60 fps. Do NOT under any circumstances run it “Uncapped”, there is a high chance it will brick your card. Obviously it doesn’t happen to all GPUs and to older GPUs but in the case with 3080s/3090s at least, they’re running hot in general and for some reason this game eats them as if it is mining bitcoins or running stress tests.
Just LOCK it to 60 fps until (if…) this gets fixed.