I was unaware of the PWM problem caused by watching OLED screens, until I recently read another thread on Reddit. I had been using OLED, Amoled, or SuperAmoled screens for the past 13 years, and didn't realize that there was a problem with them, being unaware as I was.
I recently switched phones from a Samsung S9+, with SuperAmoled screen to a '24 Moto G Power 5G, with IPS LCD screen, and though it took me awhile to accustomize my eyes to the less sharp screen (less PPI, and i installed a matte-finish screen protector on the Moto), I found that I was able to use my new phone for longer at night, without getting headaches.
I typically do genealogical research for 2-3 hours in bed, every night, for a long time now. I was getting headaches, but now I'm not getting them. I thought it was just my old eyes (75), but it may have been that I was suceptible to PWM?
By the way, consider how much you would have to disturb the brain to cause a headache. This person was getting regular headaches correlated to his OLED smartphone. The OLED screen was scrambling his brain enough to cause recurrent headaches.
Now, if you were a cunning overlord, what about using these OLED screens to covertly neuter the psyches of your underlings? They display pictures very well. They look perfectly fine. Yet covertly there is a subliminal flickering that causes quite severe symptoms in quite a number. What about the countless more with mild symptoms they attribute to other things?