@KnottyCord You are correct - you are running systemd (not plain old linux). PM2 does not seem to “realize” that.
Note that there is ANOTHER problem with PM2 that is now reported as a bug - read all about it here:
https://forum.magicmirror.builders/topic/2065/solved-pm2-does-not-start-on-reboot/10
Best of luck - and don’t hesitate to ask for help!