First, I can't see how any of the 3 packages updated would be in
any way responsible.
I assume you've already booted at least once more.
I tried 3-4 times.
Have you also re-seated video
cables? I've had unexplained video issues cleared up by doing that.
The screen is not the issue because I get the ssdm login screen perfectly well.
Also it's a laptop with an external screen. I have tested with and
without the external screen plug-in, same behaviour.
You haven't accidentally tried to open a Plasma KDE session under
wayland, have you?
I do not know wayland. I do not know how to open plasma under wayland.
Is your Logon session set to "Restore Previous Session",
"Restore Manually Saved
Session", or "Start Empty Session"?
I do not remember. I turned the computer off automatically after
backup. When I leave, I open a terminal, su to root, run dnf update,
run my backup command followed by "; shutdown" so that the computer
turns off automatically.
I tried to launch systemsettings5 from another computer but I get a
$ ssh -X alpha systemsettings5
libGL error: No matching fbConfigs or visuals found
libGL error: failed to load driver: swrast
Since you can get to a text terminal. Have you tried creating
another user and then
logging in as that user?
just done it, same problem with the new user