My setup has Immich in a Docker container, which is itself in a Proxmox LXC container.

I then have Proxmox back it up to Proxmox Backup Server running in a VM, and it has a cron job that uploads the whole backup of everything to Backblaze B2.

The backup script to B2 is a bit awful at the moment because it re-uploads the whole thing every night... I plan on switching to something better like Kopia at some point when I'll get the time