It's a shame that your 2018 monitor is giving you symptoms. Today I've been experiencing some problems with my Hisense TV that was made in 2018. I've been using it for 3 years nearly daily sometimes for many hours to watch films. I've driven it with my good laptop at 720p resolution with a refresh rate of 59hz. It is very comfortable at 720p.
But today I changed its resolution to 1080p 60z (its native resolution is 1080p 50hz) and symptoms began automatically. I then changed the refresh rate to 50hz and then it was much more comfortable to look at. I then watched Netflix for several hours and the picture at 1080p seemed more clear, detailed and vibrant than at 720p, but it was uncomfortable to look at when it was on this 1080p resolution and sometimes it gave me this pressure in the chest and a bit of a headache.
I'll try a film with VLC in the next few days to see if it's a Netflix problem, but I've used both Netflix and VLC on this TV at 720p with no symptoms at all for 3 years, so I think I have some problem with the TV's 1080p resolution. I hope the symptoms are simply stemming from what seems to be a bit of lag from using an Ideapad that has a very weak GPU and probably can't drive the TV at 1080p very well.
Some people here at ledstrain have had laptops that they can't use at the native resolution but they can use them at a lower resolution. I'm experiencing the same thing with my TV.
Anyway, I'm hoping that merely switching the TV back to 720p will bring things back to normal.
UPDATE: Changing the resolution to 1368x768 (720p) at 59.88hz makes the picture completely comfortable to look at again. On 1080p the picture was a little clearer and there seemed to be more depth to the backgrounds, but 720p looks just as good otherwise.
If anyone is having issues with their 1080p TVs or monitors, you could try changing the resolution to something like 1368x768 to see if the picture is more comfortable.