To start VNC Server now: sudo systemctl start vncserver-x11-serviced.service
To start VNC Server at next boot, and every subsequent boot: sudo systemctl enable vncserver-x11-serviced.service
To stop VNC Server: sudo systemctl stop vncserver-x11-serviced.service
To prevent VNC Server starting at boot: sudo systemctl disable vncserver-x11-serviced.service