IMHO, Debian is not the best choice for KDE, especially if you are on Wayland. KDE is a bit more buggy than GNOME, but bugs are fixed constantly at a fast pace, and Wayland support gets better. With Debian, you are stuck with the old version and have to wait 2 years for bugfixes. Kubuntu would be a better pick since it has interim releases with more recent KDE and also official backports with fresher KDE version.