Comment 2 for bug 1912773

Forgot to mention in the original post, but trying to revert all updates that caused the problem (as per the versions listed above) but that didn't work because they no longer exist in the repo (and the system had already cleared the cache). So I always get the error that the package(s) were not found:

E: Version '245.4-4ubuntu3.3' for 'libnss-systemd' was not found
E: Version '245.4-4ubuntu3.3' for 'libudev1:i386' was not found
E: Version '245.4-4ubuntu3.3' for 'libudev1' was not found
E: Version '245.4-4ubuntu3.3' for 'libudev-dev' was not found
E: Version '245.4-4ubuntu3.3' for 'udev' was not found
E: Version '245.4-4ubuntu3.3' for 'systemd-timesyncd' was not found
E: Version '245.4-4ubuntu3.3' for 'systemd-sysv' was not found
E: Version '245.4-4ubuntu3.3' for 'libpam-systemd' was not found
E: Version '245.4-4ubuntu3.3' for 'systemd' was not found
E: Version '245.4-4ubuntu3.3' for 'libsystemd0' was not found
E: Version '245.4-4ubuntu3.3' for 'libsystemd0:i386' was not found
E: Version '1:20.04.29' for 'ubuntu-release-upgrader-gtk' was not found
E: Version '1:20.04.29' for 'ubuntu-release-upgrader-core' was not found
E: Version '1:20.04.10.1' for 'update-manager' was not found
E: Version '1:20.04.10.1' for 'update-manager-core' was not found
E: Version '1:20.04.29' for 'python3-distupgrade' was not found
E: Version '1:20.04.10.1' for 'python3-update-manager' was not found
E: Version '3.192.30.3' for 'update-notifier' was not found
E: Version '3.192.30.3' for 'update-notifier-common' was not found
E: Version '0.100-0ubuntu4~20.04.3' for 'libnetplan0' was not found
E: Version '0.100-0ubuntu4~20.04.3' for 'netplan.io' was not found
E: Version '3.36.6-1ubuntu0.20.04.2' for 'mutter-common' was not found
E: Version '3.36.6-1ubuntu0.20.04.2' for 'gir1.2-mutter-6' was not found
E: Version '3.36.6-1ubuntu0.20.04.2' for 'libmutter-6-0' was not found
E: Version '3.36.6-1ubuntu0.20.04.2' for 'mutter' was not found