This has nothing to do with systemd version (and not really systemd either), you did not update for a year (which in itself is not supported in KaOS), once you did update, you replaced/updated 830 packages one of those was systemd, so makes no sense to state
Everything was fine until version 242
Not a dependency to install either, your network names have changed, thus eth0 is failing, since it looks like it is no longer available, probably
inxi -N or
hwinfo --network will show the new name.