What’s different between the 14PM and the 15PM that the former didn’t cause you eye fatigue, but the latter does?
They both caused me problems. I had to go from a 14 Pro Max to a 12 Pro max from the Apple Refurbished store. I knew from a couple of years ago after trying ALL of the 12’s that I could tolerate a 12 Pro Max.
(It was a terrible mistake to upgrade to the 13 Pro but my 12 Pro Max at the time had the infamous green screen defect meaning night scenes in videos glowed green when viewed in dimly lit rooms).
I lasted on the 14 Pro Max for almost six months but the entire time suffered some eye fatigue that eventually developed into ever worsening and persisting headaches as is typical for people who suffer from sensitivities to flickering of various kinds.
This time with the 15 Pro Max I was fortunate that everything happened on an accelerated time scale so I didn’t have a false hope I’d be okay with the phone in the long run, with only mild symptoms.
I use OLED on Android phones usually without issues. There have been a couple of phones that made me uncomfortable but by and large I’m able to use them normally.
For some reason both LCD iPhones and OLED iPhones tend to cause me problems.
Even my 12 Pro Max can get uncomfortable to use too much. If I want to web surf I usually use my Samsung S22 Ultra which has my most comfortable completely unproblematic display I have owned since the iPhone 8 Plus.