Fedora 30 boot stuck at "Starting Load/Save Screen Backlight Brightness of backlight:intel_backlight"

I recently upgraded from Fedora 29 to 30 using dnf on the command line:
sudo dnf upgrade --refresh
sudo dnf system-upgrade download --releasever=30
sudo dnf system-upgrade reboot

All seemed fine, but something went wrong somewhere…
Boot sequence gets stuck on “Starting Load/Save Screen Backlight Brightness of backlight:intel_backlight” for 30+ minutes! Not sure for how long exactly; I left it over night and the machine was booted next morning, but so slow that it is not usable in graphics mode. Mouse cannot even move in real time… :frowning:

Booting the Rescue kernel 30 works fine and the system runs as expected, but the normal 5.3.6-200.fc.30.x86_64 30 kernel is not healthy.

Any suggestions on how to troubleshoot?
Or do I just clean install?