Games play worse the longer it goes on

Current set up is an rtx 3060ti and ryzen 7 5800xt​. The only game I'm currently playing is deadlock. I've noticed the longer I run the game the worse it plays I go from 144fps to 30-50 over the course of 40 minutes. As soon as the game ends my fps usually go right back up. When this happens it also permanently freezes all other open windows while the game is running. If I have discord or steam open on my second monitor when I finish the game both will be frozen but still responsive until I close and restart the apps. Any idea how to fix this? Also incredibly new to cachy and Linux as I started last week.