Recently my Roon Nucleus stopped doing my scheduled nightly backups. In looking at this, I found I had messed up when creating another scheduled backup routine, so last night I started over. Here are the paths I put in for four different scheduled backups (Local HDD is a 1 TB USB HDD).
Nucleus > Data > Storage > Local HDD > Daily Backup (Every night, keep 31)
Nucleus > Data > Storage > Local HDD > Monthly Backup (Ever 30 days, keep 12)
Nucleus > Data > Storage > Local HDD > Quarterly Backup (Every 91 days, keep 4)
Nucleus > Data > Storage > Local HDD > Weekly Backup (Every 7 days, keep 13)
Of course, Roon backup creates a RoonBackups sub-folder for each. Nothing profound here, but might help someone think through this. I back up my Dell core manually to a folder on the Dell. And yes, this is overkill, I know.
PS: When I messed up, I might have put one of the backup routines inside the RoonBackups sub-folder of another backup routine, IDK.