>macOS has been designed to be legible and usable with a pixel density of about 218PPI (pixels per inch) for “Retina” class desktop displays. If a display’s PPI

>macOS has been designed to be legible and usable with a pixel density of about 218PPI (pixels per inch) for “Retina” class desktop displays. If a display’s PPI is higher, text and the macOS user interface will be smaller. If a display’s PPI is lower, text and the macOS user interface will be larger. Stray too far from 218PPI and macOS becomes unusable. I some ways I wish I'd never seen a Retina display. I'm cursed to buy expensive monitors for the rest of my life.