After installing updates via sudo apt update && sudo apt upgrade and then a reboot, the Kubuntu installation does not work properly anymore. I get a strange double screen on one monitor, even though both are plugged in, and do not have access anymore to any applications after logging in (see images).
Trying to access the terminal via ctrl+alt+F1 does not do anything. Ctrl+alt+F7 or ctrl+alt+F8 results in black screen. Exiting this black screen works with ctrl+alt+F1, which then for a split second shows the normal desktop before showing the double screen again.
Unplugging the second screen did not help, and neither did setting nomodeset.
Booting from an older kernel version via GRUB does work normally, and installing the updates and upgrades here does not result in the same issue.
Below the specs from the PC. The system information shows the right distribution, but an older kernel version.
