So i left this issue for a few months,
recently i've been using a dell latitude connected to the same 1080p monitor
been fine for the last few weeks 5-7 hours per day use
tonight i switched the mac mini on using bootcamp to run windows 10
holy cow my eyes are now burning up within 2 hours use
Mac mini i5 2018 have been programmed this way or is this a faulty mac?
Traditional ~100 PPI displays are worse to use in MacOS than they used to be, because subpixel font rendering was removed in Mojave. So if you are somewhat picky about text/visuals, I wouldn't step down to the non-4K panel.
this is obviously a hardware issue, that the Apple store lied about