While there's probably some overlap for certain use cases, I'd say they're more complementary. In fact, Restic leverages rclone to support a lot of cloud storage services. Restic is specifically meant as a backup tool and does encryption, deduplication, snapshots, and now apparently compression. Rclone is more of a synchronization tool/copying tool (which could also be used to make backups), more like rsync or even just cp (but with cloud storage support).