Backup restore was nightmarish. I could not make it work in situ on the NAS.
I ended up installing immich on a local docker, restoring there, and then moving the database over. Of course default immich’s docker compose defaults to postgres14, and tn uses 15 or 18, so that failed with unhelpful errors.
Anyway, it worked. data in /data/ had to be moved into one folder level above. database in default immich had to be moved into /15/docker rather than /postgres/
Rather tempted to update postgres to 18…….