Ok…
Player.log doesnt contain anything that could indicate what is going on. It looks normal.
80% usage with 80C on a 3080Ti on low quality only doing 35fps is totally out of whack… Even at 4k, that framerate shouldnt be taxing your GPU to 80% at low graphics - I’d expect that kind of usage at at least double or even triple the fps you are getting or at much higher quality settings.
You dont mention the Clock speed of your GPU when this is happening… Need to establish if the GPU is throttling itself to a lower clock speed - which would explain the usage and performance…
Also do you have any clock speed overrides in MSI afterburner ? it does have that ability (and fan profiles etc) so you need to ensure its not messing with anything… May be useful to disable it entirely and use something like HWmonitor to get the readings.
As a test, please set you in-game settings to 1080p, 60fps framerate limited (no vsync), all quality on Very Low and all special features on their lowest option or disabled. At these settings the GPU should barely be noticing anything and usage/temps should be just above idle levels… You should be getting 60fps locked at these settings on your GPU… Record, temps, clock speed, usage at this level…
Also… it would be interesting to see if anything else in your system is getting excessively hot - maybe your memory or other components are not getting enough cooling? Or perhaps the power draw is abnormally high on something CPU/GPU? HWmonitor would have all of this.
Bluescreens/Livekernel events… I am concerned about these not having a definitive reason/cause… Yes, LE in its current state can act like a benchmark and push hardware limits (especially if framerate limits/vsync are not happening) but usually it doesnt get to bluescreen levels of failure when it does that…
Your PSU may be involved - its always possible that its got a rail that is failing in very specific situations or its unable to sustain higher load of a 3080ti due to some previously unknown fault… I read up on 3080ti power draw from PSUs… and there is a potential for issues with the cables supplying the increased power to the GPU from the PSU… Long shot tho and only really effects older PSUs (even ones that have high watt rating).
Another idea - do you have any overclocking enabled in BIos?
Another thing - do you have any other Unity games? If you do, can you check if they behave the same way?