[Unit]
Description=My VNC
[Service]
Type=simple
ExecStartPre=/bin/sh -c '/usr/bin/vncserver -kill %i > /dev/null 2>&1 || :'
ExecStart=/usr/bin/vncserver -geometry 1920x1080 :%i -xstartup /home/mwo2/.vnc/xstartup -SecurityTypes None -fg
ExecStop=/usr/bin/vncserver -kill :i
[Install]
WantedBy=default.target
-fg and Type=simple are important!
systemctl --user enable myvnc@\:1.service
