Immich is running in ProxMox for me, and using an NFS mounted ZFS dataset (encrypted at rest as the rack is in the garage, unlocks on boot using clevis and tang).

That ZFS dataset is backed up daily offsite using Restic + Rclone

Immich LXC is backed up daily to Proxmox Backup Server 1, which syncs to Proxmox Backup Server 2, and also gets sent offsite.

PostgreSQL is running in another LXC container, which also backs up to PBS and also offsite.

Cron job with a bash script syncing media and the database to S3 Deep Archive once a day. Cheap as chips until you need to restore.