I'm sorry for you, but your upgrade seems to have gone wrong. apt (well, libapt-pkg5.0) certainly depends on libzstd1, so it should be there - these kind of dependencies get created automatically.
Please run apport-collect 1764858 or attach at least /var/log/apt/term.log; or read it and see yourself what is broken. ** Changed in: apt (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1764858 Title: Can't update / install / delete packages To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/apt/+bug/1764858/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs