Thanks for reaching out, and welcome to the community.
To better understand what happened here, we’ll need a bit more detail about your setup and expectations:
What type of backup did you restore?
Was this a Roon backup created from Settings → Backups?
Or was it an iTunes / system / Time Machine backup?
Where is your iTunes music library physically stored?
On a local drive, external USB drive, NAS, or another computer?
What were you expecting to be restored?
Roon backups restore the Roon database only (library edits, playlists, play history, settings).
They do not restore the actual music files themselves.
If the music files are still present on your storage, you’ll simply need to edit the path to the folder under Settings → Storage and let Roon rescan it.
Once we know what backup was used and where the music files live, we can guide you through the correct next steps.