Let me try and answer some questions
annv I switched to safe mode (when the graphic driver is probably not loaded) and felt an immediate relief. So would it is possible to turn off the AMD discrete card and use the integrated Intel graphics instead? I saw a video on YouTube about disabling the graphic card, but I do not know whether it will work on the iMac and whether it is safe: https://www.youtube.com/watch?v=9esGch26G_A
Worst thing it does is cripple your graphics performance and screen resolution.
Are Intel drivers better in terms of dithering? If so, I could switch to Mac Mini 2018. I’ve read a lot about eyestrain on MacBooks and iMacs, but not on Mac Minis. Maybe it’s just because there’s not so many of them?
That's still an unknown because emprical testing hasn't been done.
Maybe it’s just because there’s not so many of them?
Connecting a true 10-bit pro display like a NEC, so the graphic card does not need to dither.
It shouldn't need to dither, but as far as I know it still does. I want one of the NEC monitors too 🙂
Using a grayscale. It seems I’m feeling better when using greyscale (I’ve not yet tried it for too long).
Hmm maybe, but you shouldn't need to give up all color to solve this issue.
Using a VGA connection (I read in a thread here it does not use dithering).
The dithering is either performed by the graphics card or display, so it probably will still dither.'
Not a solution for now, but hopefully good prospects. There are rumors that Apple could switch from Intel to its own silicon in a year or two. Could they get the same graphics rendering as on the iPad?
I wouldn't speculate based on past products.