The stuttering happens after you play a bun of games. I assume that there are some bad memory leaks that affect the GPU. After testing about 20 games, I had to reboot my computer since even a normal Steam game would not work anymore .. had only frame rates of 1-2 FPS and 99% GPU utilization. .. Browser change did help for a little but then it was also with another browser.
I am wondering if the problems are related to 2021.3 games. At least mine is one, and another one where I looked at the code is one as well.