To be fair there are a dizzying array[0] of OSS backup solutions, and it's very much not apparently what features are most important. A simple post like this that outlines a single good enough solution with a modern tool is valuable IMO.

EDIT: Oh and restic has much more functionality than rsync, including deduplication and encryption. rclone is more of a "glorified rsync", but even then its array of backends makes it truly glorious.

[0] https://wiki.archlinux.org/index.php/Synchronization_and_bac...