Do I need to run it from source to leverage systemd so it's always running as a service? No, you can run any version this way. The service script is only to manage starting and stopping an application automatically during OS startup and shutdown. You don't need it however. Just run the SABnzbd exec...
Can you guide OP how to do that? Already covered in the wiki: https://sabnzbd.org/wiki/installation/install-off-modules Just need to use the SystemD service file: https://github.com/sabnzbd/sabnzbd/blob/master/linux/sabnzbd%40.service Mine looks like: # copy or _hard_link to # Debian: /lib/systemd/...