Restart xfce from tty1

For me startxfce4 didn't work, but pkill did.

You could try the following command:

xfwm4 --replace

It restarts the windows manager.

pkill worked but seemed a little extreme to me. If I had other stuff going on in other tty sessions, it would kill those too.

Another solution is:

sudo systemctl restart lightdm

A great strength of Linux is that there are always multiple ways to achieve the same task.

Try killing user by

pkill -KILL -u yourusername

This will bring you back to login screen though.