I have the same computer, but with 16GB RAM. I’m on the latest version of Monterey and have been having similar GPU issues since spring of this year. The issue is way more prevalent in Hearthstone (daily), but occasionally strikes in WoW as well (a few times a week), and sometimes in standard Apple apps. I do have a second monitor, but I’m never running any video at the same time.
The freezes can occur with no other applications open other than the game. The freezes even occurred without a second monitor attached. The issues have presented in multiple different ways each time (sometimes a brief freeze, sometimes a freeze and it will return to the game as usual, sometimes a freeze and red screen followed by a kernel panic, sometimes a freeze and it will return to the game with a red screen and I can hear the audio of the game but see no video, sometimes I have bizarre artifacting, sometimes it looks like a shattered glass appearance glitching out, other times it looks like a rave flashing across the screen, sometimes it goes completely gray and half of the main monitor returns. Sometimes only one monitor is affected, sometimes both.
All the diagnostic logs show repeated GPU restarts, and occasionally a kernel panic. I’ve reformatted my computer at least 3 or 4 times. I had my logic board (which includes the GPU) replaced twice, as well as the RAM out of precaution (AppleCare makes it “free,” thank goodness.) I just picked it up two days ago after the second repair and am sad to report the issue still persists.
I submitted several logs to Apple support and the engineers reviewed them after the first repair, stating that nothing indicated it was a software issue, and it must be faulty hardware, which is why I had to replace the logic board again. I’ve been experiencing this since March or April in at least 3 games (one non-Blizzard) and has only gotten progressively worse. It is very frustrating and wish I had a solution.
There was another thread in this forum about constant freezing in Dragonflight zones on the same exact machine and I’m starting to wonder if there is some major defect or issue with our model or the way something interacts with our machine. I got the computer in 2019 and haven’t had these graphical issues until earlier this year.
I’m going back to the drawing board with the support rep again tomorrow, I guess. Just hoping to add some data points here in case it helps.
Edit: I forgot to add that I use my 16” 2020 MacBook Pro on Big Sur with the same exact monitor configuration and peripherals and apps and never experience the freezes doing all the same tasks.
Edit 2: I realize the issues started around when I installed Monterey because I was forced to update, as Catalina froze in Zereth Mortis, which was launched late Feb of this year. It has gotten progressively worse since. I have tested pretty much everything I can think of, even things that aren’t relevant. I had a kernel panic this morning attempting to use Safari in case Chrome was problematic, however it used like 10x the resources of Chrome and crashed the machine, and half the time Chrome isn’t even open when a crash or freeze occurs, so it was just a test.
OP, did you skip over Monterey from Big Sur or did you not have issues on Monterey?