Using `kdePackages.*` (Qt6) instead of `libsForQt5.*` not working under wayland

I recently removed libsForQt5.<package> (Qt5) and replaced it by kdePackages.<package> for all packages that are available in the latter.

However, they don’t work, e.g.:

> okular
qt.qpa.plugin: Could not find the Qt platform plugin "wayland" in ""
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: minimal, vnc, vkkhrdisplay, offscreen, eglfs, linuxfb, xcb, minimalegl.

With

> QT_QPA_PLATFORM= okular

okular starts in XWayland mode.

This is the typical symptom when said packages are not compiled with qt-wayland support as I recall, but I doubt such an obvious omission for standard KDE programs could be present in nixpkgs?

I guess such things should be handled by (the new?) mkKdeDerivation, but apparently it isn’t?

I’m running Hyprland since ages (with manually set QT_QPA_PLATFORM=wayland for the entire session), and have had relatively few wayland issues, apart from some “niche” packages like FreeCAD (Qt5) for which I have submitted nixpkgs fixes because wayland was forgotten…