I've been using it for about a month, and love it.
My one complaint: self-signed certs on reverse proxies seem to break the android app backup. I'm not sure why, but internal CA seems to make things angry. Its more likely to be a local setup issue than anything in immich, but frustrating to pin down.
All the traffic is internal, so I can get away with it ๐
Really was just interested in what cert generation entailed and did a fun little dive a few years back.