Syncthing synchronizes files between devices. Its own FAQ warns that it is not a great backup application because changes and deletions propagate. That is helpful when you want the same working folder on two machines, but dangerous if your only other copy mirrors a mistake.

restic is a backup program built around repositories and snapshots; its documentation describes encrypted backup storage. It is not a live collaborative folder. You must decide when to run backups, where to keep the repository and how long to retain older snapshots.

Choose Syncthing for moving an active folder between your devices, and a backup workflow such as restic for returning to an earlier state. Combining them can make sense, but keep backup credentials and storage separated where possible so one compromised device cannot erase every recovery path.

Before relying on either setup, create a harmless test folder, change and delete files, then attempt recovery to a separate location. Check storage, scheduling and password custody. This is a documentation comparison, not a speed benchmark or a claim that encryption alone defeats ransomware.