Holla Paulo,
Welcome back!
In these days, it isn't necessary to do an "apt update; apt full-upgrade" outside X, normally not.
If you want to shut down the xserver, you need following command
"systemctl isolate multi-user.target" and go back "systemctl isolate grapical,target"
But take care, a "python" transition is going on and a "kdepim" transition, read what apt wants to do!