So this has been happening since I got my new PC built (Ryzen 5 5600X & Gigabyte RTX 3070 Gaming OC) and has finally got on my nerves. Basically whenever I have a game opened with borderless windowed enabled (doesn't happen with fullscreen) I will get flickering on any type of web browser (Edge, Firefox and Chrome) every few seconds, it is sort of random, but usually happens with inputs. Non-surprisingly disabling hardware acceleration in the browser 'fixes' the issue, but I'm not taking that as a fix since it's quite an important feature for websites like Twitch. I've had no problems or any sorts in the games themselves (no artifacts, flickering etc) so I really don't think it's the GPU itself. I found a reddit thread with what looks to be the same issue so I don't think I am alone.