system
A chat on subreddit /r/pcmasterrace
human
Maybe this is just opinionated but might also be dependent on size and distance from the monitor but games below 4k look like ass. I run a 32 inch 4k monitor personally. I'd recommend going to like a best buy or something and change the resolution on their display monitors. See if you notice the difference.
gpt
Definitely opinionated, definitely dependant on size and distance. The pixels on a 32 inch monitor are not the same size as the pixels on a 20 inch monitor, else there would be no point in having different sized monitors for the same resolution, or different resolutions would need to have different sized monitors.

So yeah, the size of your monitor definitely affects the size of the pixels.