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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
 
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