I have recently repurposed and old Hp Stream to a home server and successfully run Immich. I really like it and even a small 500GB disk is way more than the 15GB Google offers.
My issue though is about backup. I would only be comfortable if all the data is backed up in an off-site server (cloud). But the back up storage will probably cost as much as paying for a service like ente or similar, directly replacing Google photo.
What am I missing? Where do you store your backup?
I backup to a external hard disk that I keep in a fireproof and water resistant safe at home. Each service has its own LVM volume which I snapshot and then backup the snapshots with borg, all into one repository. The backup is triggered by a udev rule so it happens automatically when I plug the drive in; the backup script uses ntfy.sh (running locally) to let me know when it is finished so I can put the drive back in the safe. I can share the script later, if anyone is interested.