I’ll share my experience with my very unprofessional but working setup.

I have two locations, both using retired PCs. I don’t need anything fancy, but some considerations could be GPU/encoding hardware if you wanted something like jellyfin/Plex. I use proxmox and proxmox backup server for managing everything and so far it’s been working well. Definitely not plug and play like an aio nas but that’s because a nas wasn’t my only goal as I needed cameras (frigate) and homeassistant.

I would highly recommend headscale/tailscale (as others have suggested) as it “just works” when setup in my experience. This enables safe remote access without opening any ports on your families networks so you can troubleshoot if something did break.

Regardless of which solution you decide to use, the most important part about having a backup is testing. If you can’t see when your backups fail or don’t know how to recover you may as well not have a backup.

I use headscale and it’s been working wonderfully for my nightly offsite backups and remote access.