Thank you all for the interesting discussion and a lot of hypotheses.
The topic of allergies came up. I perceive my symptoms as a defensive reaction of my brain. It looks a bit like an allergy to specific screens. When it comes to allergies, even after years of using something, eating something, etc., allergy symptoms can occur. This was the case with my cholinergic urticaria. One day I just got it. It's sensitivity to sweat, and yet people sweat every day.
Yes, I have used screens that were bad for me, but if they made me sensitive to good screens, it must have been a long process but with a sudden effect. I tested the first phone in April, and the last one (the best for my eyes) in early June. The good screens became unbearable in mid-June. When I was testing the phones, I also was using the Switch OLED and Steamdeck and had absolutely no problems with them. I don't know if I mentioned, but the screens of my consoles have completely different parameters (different frequency, modulation depth, etc.), but the symptoms are identical.
My case is difficult because there were a lot of variables in a short period of time. Have contact lenses made me sensitive to light? Maybe it's a reaction to antihistamines? Maybe I've been using the wrong screens for too long. Or maybe all at once?
I'm going to test my bad screens, looking for the cause of my problems. If I figure something out, I'll share the results here. Maybe this will help someone.
For now, I have stopped taking antihistamines and put moisturizing drops in my eyes. The day before yesterday I used Nintendo Switch for about half an hour. The next day my eyes hurt and I still feel some discomfort today. So nothing has changed for now.