Yes, this works and people do exactly this — but a few things will make or break it: Borg client-side encryption solves your trust worry. The Pi only ever sees encrypted chunks, so it doesn’t matter that it sits on a family member’s network. They can’t read a thing, and they can’t even see file names. (This is the answer to the “you need to trust the remote household” concern — you don’t, that’s the whole point of Borg’s design.) NAT traversal is the real friction. Your NAS can reach out through the tunnel to push, which works if the Pi side has the tunnel endpoint reachable. Easiest reliable options: have the Pi run Tailscale (zero config, works behind any router the family has), or have the pull direction — Pi connects to your NAS and runs borgbackup --client style pull. With plain WireGuard between two home NATs you’ll be fighting dynamic IPs and CGNAT. Seed at home, then let deltas flow. Format the disk and do the first borg init + full backup at home. Borg is content-addressed and deduped, so after the initial seed, daily backups over any normal WiFi/DSL line are just a few hundred MB of deltas. No need for a VPS unless the family setup becomes unreliable. One caution: a Pi Zero on a shared WiFi will eventually get unplugged or the router rebooted and you won’t know. Add a dead-man check on the NAS side (e.g. a cron that alerts you if the last successful backup is > 48h old). The failure mode of “offsite backup silently stopped 3 months ago” is unfortunately the most common one.