Can not login KDE desktop after upgrading

[bbaudio]

I have not use my kubuntu24 in months, today I booted it and did apt update && apt upgrade, everything was OK, after the upgrade there was a tip notified me to reboot, well, I rebooted it.
And then the problem came up, there was only a mouse pointer on my screen, the rest was all black, no login menu and I could not input password. Yes I could move the pointer, but no matter what I clicked or pressed, there was no response.
Fortunately I can use tty by ctrl+alt+F2, but I don't know how to get in the plasma desktop from tty. Can anyone help? Thank you.

[claydoh]

Try a previous kernel at your grub menu. A common breakage point are kernel security updates.

to try getting to a desktop in the new kernel:
at the tty (NO! SUDO!)

startplasma-x11

or

startplasma-wayland

Whichever is appropriate
You may see errors, which may point to what is happening