I've noticed that problem could be not in monitor but in video card and drivers. I have been using my phillips monitor for the last 3 years with ryzen 7 6800h and gpu 680m inside and i had no eye strain, now i bought egpu with external nvidia card 5060 and It gives me eye strain and headaches after 10-20 minutes with the same monitor. I suggest that is temporal dithering by nvidia drivers. I also tried asus nuc pro with intel arc 140T gpu inside - same result eye pain and headaches. Theare are a lot of dithering algorithms, some of them are using and FRC in monitors but it's easier for eyes.