Since the update to Manjaro Stable of 28.04.2021, the order of the character-mode virtual consoles and of the virtual console where KDE Plasma is running is off by 1.
/dev/tty1 is now uninitialized ─ it doesn’t even show a login prompt ─ and Plasma is now running at
/dev/tty2, as you can see below.
[06:05:19][aragorn] > who
aragorn tty2 2021-04-29 05:52 (:0)
aragorn pts/0 2021-04-29 05:52 (:0)
aragorn pts/1 2021-04-29 06:05 (:0)
aragorn pts/2 2021-04-29 05:55 (:0)
The first usable free virtual console is
[Stable Update] 2021-04-28 - Kernels, Wine, Ruby, JDK, KDE-Dev, Mesa 21.0.3, KDE Apps 21.04, Python, Haskell, Mate 1.24.2, Virtualbox, Thunderbird
It seems the same issue is present in testing and unstable, so, apparently was not obvious to anybody else (including me) before this mention of it from you.
Same on arch:
FS#70528 : [sddm] switching vtty does not activate graphical session
08:42PM - 21 Apr 21 UTC
Xorg is started on tty2:
$ ps ax | grep Xorg
600 tty2 Ssl+ 4:25 /usr/lib/Xorg -nolisten tcp -background none -seat seat0...
This issue has now been resolved with the 2021.05.06 Stable Update, so I’m closing the thread.