Desperate to finally and permanently fix an issue relating to what I currently think are "full screen optimizations." After... years... lol

So essentially, one day all of a sudden out of the blue - my screen would pause for a moment randomly at the start of the game, when i opened settigs, or randomly on its own at some point during the game.

At this point, my mouse would go crazy. I will spare you the story of everything I tried and investigated. Often, something I'd done would temporarily fix the problem, but it always comes back.

Skip to now, where I currently have something of a consistent work around (for now). Every game, if I toggle "disable fullscreen optimzations" off and then on again, it seems to work correctly for that game.

I am wondering if anyone can help point me in a direction from that information to finally solve whatever the underlying issue might be.

Thank you!