[solarkraft]

Works perfectly on Wayfire and I assume Sway.

I briefly tried out Gnome and KDE, with the former "meh" (no fractional scaling, scaling glitches when dragging between displays) and the latter garbage (couldn't find scaling settings at all, so nothing is readable on the laptop display).

Widows is between "okay" and "nice" (somewhat fractional scaling, glitches between displays, some wrong scalings, but it's rare).

I haven't tried macOS yet, but expect it to be flawless, like or slightly better than the experience on Wayfire.

[sho_hn]

Fwiw, System Settings -> Display has the per-screen scale settings.

My wife got a 4K desktop screen for her FHD laptop a few months ago and it made us switch her system to Plasma's Wayland session. Mixed DPI works fine, also dynamically (i.e. dock/undock).

[COGlory]

KDE scaling settings are pretty obviously in the Display Settings page so I'm going to say that one is user failure.