I don't understand why people say that ; I had my first hidpi screen in 2014 and it worked fine from day 1 on X - to the extent apps & toolkits themselves supported it; the only two that took their time were chrome and firefox but even today they work fine ; the last remaining bastion is TCL/Tk but this does not even work natively on wayland anyways.

here's how it looks for me today on X11 : https://i.imgur.com/VfWisJ7.png

I would gladly make a comparative sway screenshot but it is unbearably slow on my machine (maybe due to nvidia drivers), the keymap is incorrect, and half the programs I want to use don't even launch