iMac 2017 is the most eye-straining device for me. I've accustomed to it little by little, but only after applying some tweaks (Gamma Control with max brightness, color profile, native resolution, etc.). I hope one day I can find a way to switch off temporal dithering on it.
I tried to use this Mac in BootCamp recently, and to my surprise, it was much worse than under macOS. I felt strain after one hour (that didn't happen before: on the same machine BootCamp was much more relaxing). Scrolling was especially straining. I think this screen applies some PWM below max brightness. Plus it's a slow matrix. So it might be a hardware issue. People at MacRumors mentioned "screen lottery", meaning you may get a good or a bad Mac. I didn't try other Macs though, except in the store.
As to mobile, I do not have strain from iPhone SE 1st Gen and iPad 6th Gen (2018), but I generally feel that my old Moto is more relaxing for the eyes. Not that bright and vibrant. My impression is also that with every version iOS has more and more vivid and bright colors. Right after I upgraded iPhone SE to iOS 14, I had to turn the brightness down a bit. Also, scrolling is easier on the eyes on Android.
Among other Apple devices that I tried in the store, I did not like iPad Pro 2018 and MacBook Pro 16 (some sort of dizziness immediately). So this might be in line with the others' experience.