Btw, everybody who I know, and I too, changes the font size, and leaving the DPI scaling on 100%, or maybe 200% on X11.
Doesn't work if your screens are too different (e.g. 4k laptop screen and 32" desktop monitor).
I switched in 2018 and was surprised I couldn’t use fractional scaling on one monitor like I’d been doing for years on windows.
I don't really care about this but here's an example:
I have 2 27" screens, usually connected to a windows box, but while working they're connected to a MBP.
Before the MBP they were connected to several ThinkPads where I don't remember what screen size or scaling, I don't even remember if I used X11 or Wayland. But the next ThinkPad that will be connected will probably be HiDPI and with Wayland. What will happen without buying a monitor? No one knows.
The post is from the Dev of i3wm an x11 window manager complaining among other things about how well his 8k monitor works under x11 and how poorly it works under Wayland.
You can also consult the arch wiki article on high DPI which is broadly applicable beyond arch
