• Display Manager - Arch Linux
• LightDM
• GDM
• Mint Display Manager
• sddm for kde

• Some Common Ubuntu Display Managers and How to Switch Between Them
• Switch Display Manager in Ubuntu 20.04 - TechPiezo
• dpkg-reconfigure <DisplayManagerPackageName>으로 완전 재설정 가능하다. /etc/X11/default-display-manager에 있는 값이 변경된다. 직접 변경해도 됨.

sudo dpkg-reconfigure gdm3 # /usr/sbin/gdm3
sudo dpkg-reconfigure lightdm # /usr/sbin/lightdm
sudo dpkg-reconfigure sddm # /usr/sbin/sddm