Plasma 6 has come to Debian Trixie (Debian Testing) but breaks the desktop. After I updated it was upgraded from Plasma 5 to Plasma 6 but the desktop was broken. Many of the core software settings were missing. It seems I was not the only one who had this problem. Debian sometime keep packages back from testing but not from Debian Sid (unstable.) Here I explain how to solve the problem.
Here is more information regarding this:
https://wiki.debian.org/Plasma%206
/ what_happened_with_kde_on_trixie
00:00 Intro
12:26 The Problem
17:24 Missing Packages
21:16 Debian Trixie Live CD With Plasma 6
26:54 Other Options
27:40 Install Another Desktop Environment
30:38 Upgrade To Debian Sid If You Want KDE
32:16 Reinstall Debian Stable
34:10 Summary