Comment 57 for bug 1848534

I don't have much knowledge bout systemd, either :-) I just did a "man systemd" and found the options of systemd. "man systemd" says that we can use pass these kernel parameters to systemd:

systemd.service_watchdogs=true systemd.show_status=true systemd.log_level=debug systemd.dsystemd.default_standard_output=kmsg systemd.default_standard_error=kmsg

I tried these by adding them into /boot/grub/grub.cfg manually, at the end of the line "linux /boot/vmlinuz-5.3.0-23-generic ...".
I also replaced "quiet splash $vt_handoff" with "ignore_loglevel". So I can get more messages from systemd, but not so much as I expected. Not sure if this would be helpful to troubleshoot the long delay issue for you, and I'm not even sure if I enabled the systemd loggong completely correctly -- again, I'm not really familiar with systemd. :-)

To stop/disble a systemd "service", I think we can use something like this (taking the setvtrgb.service as an example):
  systemctl stop setvtrgb.service
  systemctl disable setvtrgb.service
  systemctl status setvtrgb.service