SDDM fails to start Plasma Wayland when SDDM is restarted

I was always on X11 'til the release of Plasma 6, so I’ve just experienced what seems to be a bug dating back to 2017? SDDM fails to start Plasma Wayland when SDDM is restarted · Issue #890 · sddm/sddm · GitHub . The last comment was:

looks like a Plasma bug. The plasma session should end its processes like other desktop environments do.

Is there a follow-up to this?

Basically I did a systemctl restart sddm which worked one time /edit: not even sure, but every sequential time I would be presented with a black screen after entering the password. I can provide more details ofc but I suppose there is a place where it is already discussed, so that I can follow it? Can’t find something in, there are many various sddm/wayland/kwin bugs so I’m kinda lost. Thanks in advance.

Tested it in a fresh Neon VM (Plasma 6.0.3), in an Arch VM and in my Arch system, even with lightdm instead of sddm, all behave the same.
(Though in bare-metal Arch (amdgpu) there are additional weird things going on, like not restarting the session in tty1 but applying a X11 session instead while the password box in SDDM on tty2 awaits input, several sessions listed as “closing” in loginctl etc.)