You don't need a fancy monitor to not strain your eyes. You know you need? Lower brightness or more ambient light.
This is something I've been saying for ages. Some time in the last 10 years or so, it seems we decided as a collective that screens should be SUPER BRIGHT, and now half the tech crowded uses dark mode.
If you "just like dark mode", that's fine. But if you avoid light mode because it hurts your eyes, then your brightness is too high or you don't have enough ambient light.
I sit at my computer 12-16 hours a day. Yes, I know, it's pretty unhealthy. But I have never felt eye strain. Even after getting LASIK and my eyes were a little more sensitive to light, I could stare at my screen all day after the first day.
But at least the brightness setting should be easy to reach then (preferably analog dial). In my current monitor, the only way to adjust it requires multiple tiny 4 way joystick button presses to reach the correct space in the menu. No direct controls. The only direct control is for volume, while one would never want to use this monitor for sound (super tinny hdmi speakers). No option to even assign this control to brightness.
Most modern displays support DDC/CI or whatever it is that lets your PC talk to the monitor and adjust brightness (and other settings).
Monitorian and other apps let you adjust those settings from your PC.