I've tried checking the box "don't ask for password on login"
I've tried this: https://askubuntu.com/questions/51086/how-do-i-enable-auto-login-in-lightdm/456957#456957
I've tried editing this file /usr/share/lightdm/lightdm.conf.d:
[Seat:*]
greeter-session=slick-greeter
autologin-user=opac-kiosk -I added this line
Any ideas? Seems all the instructions I've found are for 18.04 and earlier.