That is really amazing that there could be a source of eyestrain when there is no PWM and no temporal dithering type of flicker, but still eye strain, whereas in the other there clearly seems to be temporal dithering or some other flicker and no eye strain.
Why it is so impossible to find out the reason for the eyestrain.
This goes without saying but this is such a frustrating problem.
Like with my Lenovo x280 - tried another speciment of the sam x280, but it had a different panel without PWM, but still produced massive eye strain, whereas the lower quality panel does not.
Though, teams video does produced eyestain and I suspect any video, but I have not really tested. I have not tested because it would require some 4 hours of e.g. Netflix watching and then if it produces eyestrain, my eyes would be screwed for 2 days.