This is without a doubt the best screen I have used in years. I am so happy with it.
I think the reason is really the refresh rate and some inserted frames that the monitor manufacturers insert to reduce ghosting.
E.g. on my LG monitor I have a setting for "response time" (which should eliminate ghosting) and one for "1ms motion blur reduction". Both add some sort of black intermediate frames that produce flicker.
With 240Hz and these settings to "off" the image is very stable.
I think the refresh rate would also explain why my eyes feel so comfortable with an iPad Pro. As far as I understand it also has a higher refresh rate (up to 120Hz).
I will update you about this in a few days. Need to do my tax declaration. So there will be a lot of sitting in front of the screen now...