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 have my Immich library backed up to Backblaze B2 via Duplicacy. That job runs nightly. I also have a secondary sync to Nextcloud running on another server. That said, I need another off prem backup and will likely run a monthly job to my parents house either via manually copying to an external disk then taking it over or setting up a Pi or other low power server and a VPN to do it remotely.
So you just mount the immich folder in the duplicate container? Or run it native?