EPG (Guide Data) Not Showing - Database Error on fresh install

The db is on a different system, accessed via SMB or NFS?

That will lead to database corruption.

See Linux Tips: Plex’s metadata on a network share. (Advanced users only)

You might be able to use iSCSI, since it appears as a local drive to the system. I’ve no experience with iSCSI, so don’t know how well it works (or doesn’t).