I'm guessing this is largely due to frame gen, but I wouldn't be overly surprised if the upscaling itself was a problem for some. Is it just DLSS OP, or do you get similar with FSR or XeSS? As mentioned, frame gen on or off? Which games are you talking about exactly, do you play a ton of different where it always happens or just one or two?
It probably seems odd to many, but there are a couple of games that trigger literal migraines (I am prone to them) if I play them for more than short periods of time. Half Life 2 is the biggest culprit, I have played that game since it launched on a myriad of different hardware setups and to this day spending more than 30 minutes starts setting off twinges. There's a couple of other titles that have done it over the years also, and it's not even specifically the source engine as I have no real issue playing for example VTM:B.
Our brains are all wired differently and sometimes weird stuff can set things off in a negative fashion, I'm certainly not equipped to explain why but having experienced strange gaming related problems myself I do get it.