My Immich server performs a nightly backup to a 2tb flash drive labelled "PHOTOS" attached to the router. My partner knows where it is and what it's for, and everyone knows how to use a flash drive.
My server sends me notifications for every update with the rsync output so I'll know if any problems arise while I'm around. The last drive in this position lasted 4 years without incident, and I only replaced it earlier this year because it was full.
I’m trying to archive, document and make accessible family photos, but fear any work I do organizing information in immich may as well be throwing it into black hole.
I back up the complete Immich filesystem and database, and include a docker-compose.yml, so if it was handed to someone technically inclined they'd have all that.
I feel the same, so I keep photos on hard drives and usb drives in different locations. I have a Restic backup at Backblaze but that is where the bus factor comes in. I don't know what would be best.