Automatically log in to dom0/XFCE on boot
Edit /etc/lightdm/lightdm.conf and uncomment and set autologin-user=dom0-username
Logout, lock screen, and suspend works as normal where you need to use your password, but booting the system will skip the lightdm login prompt and boot you into the desktop without you having to enter your dom0 user password.
Your LUKS password is still be needed to boot the system.