I wish they would better support external image sources - images not uploaded/managed by Immich, just a folder of images it has access to - especially if it's read only. It mostly works, but the UI and logic breaks in a lot of little ways.
I "restarted" maybe twice when I first got into Immich to find a good set up for playing reasonably nicely with external libraries, but it does need just a bit more polish. Good to see a sibling comment that it's on their list of priorities!
Hackers
The coolest thing I've done with Immich is just set up Docker on a more powerful machine, run the machine learning libraries, and point my instance (on a low powered server) to use that external computing for face recognition and OCR. Very cool!