Gnome is the only linux desktop environment that got 4k (sort of) right. If you don't like gnome then you are on your own. I use sway/wayland for work and i3/xorg for home and I got them to work in 4k after days of customization. Wayland, X, sway, each version of gtk, qt, and various apps all have their own configuration, each which need to be configured separately, often with conflicting results, and when finally functioning, still don't work very well.
I set base DPI to native. Then set GDK environment variables to scale up to double so UI and fonys aren't tiny in apps like chromium. QT scaling env variables, and the Trolltech conf for font size in apps like Beyond Compare. Then a HiDPI font config for Gimp. Each version of GTK has its own dconf settings. Then there's Firefox which requires an environment variable for HiDPI in wayland. Mouse cursor size must be configured in both Sway and X. Font size for terminals like Kitty. Display managers often have their own separate config, e.g. SDDM. Its a nightmare.
