Eye strain from every non-apple display???

Alright this is a mystery to me, can someone please give me some tips?

Basically the devices I have now are a 2020 13 inch MacBook pro, a 2020 iPad Air and an iPhone XS. 

I love all these, but I realized that I needed more screen real estate for my uni studies.

Sure, no problem, I’ll just get an external monitor I thought! So I go on to buy the Samsung CJ791, ultrawide curved display, 34 inches, 1440p, VA panel, flicker free, thunderbolt 3 capable. Great. I get it delivered, plug it in, and enjoy the experience...for about 20 minutes. After which I get some major eye strain. I try bringing down the brightness, changing contrast, sharpness, turning on reduced blue light mode, changing the height of the screen position to be the most ergonomic, changing my viewing distance from the screen. Nothing helps. I get major eye strain and headaches. Now mind you I use my Macbook 9-10 hours a day without any sort of eye strain issues. I conclude that the text is too small on the Samsung, that is what’s giving me the eye strain. (OS does not allow scaling for non 4K displays.) 

I decide to return it. This time I look for a dual monitor setup. I go with two BenQ EW2480 displays, IPS panel, 1080p, 24 inches, equipped with all sorts of eye saving tech. Scaling is now great. Surely must be perfect. But no! I still get eye strain. A bit less of it, but still enough to give me a headache. WHY?? I reduce the brightness, apply blue light filter settings, try different viewing distances (60-80cm). No help. 

At this point I am desperate. How come I get no eye fatigue whatsoever from my MacBook, iPad, iPhone but whatever monitor I buy kills my eyes? Is it that my eyes are not used to large monitors? Is it that my eyes are used to 200+ PPI? Do apple displays have some kind of eye saving magic in them? Aren’t they also IPS displays just like the BenQ pair i just bought? Am I used to viewing my display from up close whereas I need to view monitors from further away? Do my eye muscles need to work less when viewing a smaller display compared to a larger one?

I also wear contacts (-2,5) if that might matter.

Does anyone have any ideas? I am eternally thankful for any help at this point!