Likewise, what mostly fixed it for me was; Don't use WASAPI shared mode, use fullscreen, if you're using lightning mode, set your refresh rate to 120 (instead of 144/240/whatever), close other programs in the background that may try to draw things on the screen, like Discord or Telegram for notifications, & try to avoid having programs open with a heavy workload, or high drive usage. I also noticed that sometimes Windows Defender will try to run a surprise virus scan in the background, and that will make me de-sync too.