I’ll assume your core is now Roon 1.7 B500.
All Roon remotes now also need to be on Roon 1.7 for them to connect.
Could you confirm what version your remote is running and if not 1.7 upgrade it.
Once upgraded it should be able to connect to the core.
Roon backups; I recommend setting up Roon to make scheduled backups.
This is done from the Settings --> Backup screen.
I would definitely refer to @Carl’s suggestions for a good starting point. If you need any further assistance after following his suggestions, please let us know and we can take a look.