After last (today) update i can not normaly boot.
Update was about qt5 on fresh version (i can not see details)
I have the same issue. I can only see a cursor and a black background in this update.
Try switching to a tty console (Ctrl + Alt + F1).
Log in and try an update again:
sudo pacman -Syyu
Reboot (Ctrl + Alt + Delete)
Everything is ok:
https://forum.artixlinux.org/index.php/topic,3781.msg24503.html#msg24503
Problem solved.