>macOS is able to achieve consistent sizing across displays irrespective of pixel density because it . . . downsamples it proportionally for each screen For me

>macOS is able to achieve consistent sizing across displays irrespective of pixel density because it . . . downsamples it proportionally for each screen For me, the most important consideration is to complete avoid downsampling -- because it makes everything blurry. On both macOS and Linux, the way I do that is to choose to scale the UI by an integral factor (usually 200% in my case) and then (since 200% makes things a little bigger than I prefer) fine tune the apps in which I spend most of my time (namely, Emacs and my browser). Specifically, on Linux, Emacs relies on GTK to draw its window, which IIUC cannot do fractional scaling, so if I were to set a fractional scaling factor in Gnome Settings, then Emacs would be blurry whereas there is no blurriness when I set an integral scaling factor in Gnome and use something like (set-face-attribute 'default nil :height 90) to adjust the size of text in Emacs.