Like Cosmic Desktop (POP OS!), automatically switch to some "High DPI mode" when detecting appropriate setting. Ex : I have a laptop with an 15.6" screen with 3840x2160 resolution. In this native resolutions, elements on screen are very very small so the desktop is unusable as is. When this sort of setting is detected, automatically adjust global scale to have something usable (in this example, global scale of 200 % is right). As in Cosmic Desktop, a notification would be shown when activated, in order to be dismissed by the user.
Already done on Wayland; the bug report tracking this for X11 is Bug 422552. *** This bug has been marked as a duplicate of bug 422552 ***