Sorry about a mistake, the default desktop is indeed Gnome - Wayland (no Qt here,
mistake)
but if one uses a Qt-based app, then all these issues are very real.
So Gnome - Wayland is ok, as long as Qt apps are *not* used.
The issues is not in KDE, but somewhere between Mutter - Wayland - Qt.
Fedora default desktop should be able to run correctly most applications.
If Qt applications cannot work properly in the default desktop, then it (the default
desktop) should be configured to run Qt-based application in the X11 emulation.
We are talking about a big GUI framework, not some unknown library. If GNOME/Wayland
cannot cope with it, it should either not be the default or ensure Qt apps are run in the
X11 emulation.