I'm running it on laptop with Intel+Nvidia hybrid graphics. I had Steam on iGPU for ages before I realized, recently switched it to Nvidia but haven't seen the flickering. I remember someone mentioning that it might have something to do with mouse polling rates or something, but I have a really cheap mouse so I might be too cheap to face that issue haha.
No issues in games, it's the steam client which has issues.
Now that I remember Firefox extensions too are having issues with overlays (bitwarden) but I've not updated my system in a couple of weeks which might to be to blame here.