I experienced the same issue with the Alienware 27" 360 Hz OLED monitor. While it was great for gaming and I loved the refresh rate, it was terrible for everything else. Text always looked blurry, my eyes would keep trying to focus it and tired themselves out. I started getting headaches and began to doubt my prescription. After months of investigation, visits to the optometrist, I finally narrowed it down to the monitor being the culprit. I gave it away to my son, who on the other hand was thrilled to receive a bonafide gaming monitor. He uses it at 2x scaling and couldn't be happier.

These monitors are great when scaled but have real issues rendering text and other fine details at their native resolution.