Same here OP. I think you are on to something. The easiest answer would be to stop playing or turn off the monitor and get a new one. However, i think this is something important and worth discussion. It's a condition that a lot of people may have and think it's normal and don't think into it too much. Not even sure if there's a diagnosis name for it.
The display i use is an Asus RoG 144hz 4k HDR Gsync. Yeah it was quite a few dollars but the quality is the best and the refresh rate makes game(s) smoother. The problem is, i get tired while playing certain games. My eyelids get heavy all of a sudden and i shut everything down and go sleep, even after only a few minutes of playing. It doesn't happen with all games though, that's what's weird. The games that do trigger the tiredness the most from what i have experienced are, in order of severity:
God of War (PS4 Pro. I haven't been able to experience the game much because it makes me fall asleep within 5-10mins of playing)
No Mans Sky (all versions)
Resident Evil 7 (all versions)
Red Dead Redemption II (both versions although the XB1X the symptoms aren't as bad as playing it on the Pro)
Nintendo Switch (handheld mode. I cannot seem to play any games without falling asleep. Playing it on a television doesn't cause the tiredness symptoms)
Assassin's Creed: Odyssey (any version, i have it for all consoles)
Grand Theft Auto V (PC version)
Mass Effect Andromeda (PC version. The console versions don't seem to cause the tiredness)
Dishonored 2 (PC)
Spiderman (PS4 Pro)
Far Cry V (all versions)
Games that don't trigger tiredness symptoms, from what i have experienced:
Battlefield V (PC version)
Company of Heroes 2
Factorio
Uncharted series (PS4 Pro)
PSVR:
Astrobot Rescue Mission
Wipeout VR
In 2011 i was in an auto accident that among other injuries, left me with a severe concussion. I regularly get bouts of dizziness and/or balance issues due to damage of my equilibrium. I take medication(s) for it but anything can trigger dizziness and unbalance feeling, even reading a book. I used to be able to game for hours on end before the accident and now it's pretty much selective in what i can play/tolerate. I think i have to play games which require more brain nerves firing up or something to make me think, otherwise the cells get tired/stop moving or something, idk. Could be something to do with my monitor, some kind of technology it has that i haven't configured correctly, idk.
Maybe it's something to do with WWise, Havok? or some of the other things imbedded into games that are shown at the opening or ending introductions.