I use LibrePhotos in my home server. I did not know about Immich, either.
Although LP is updated que frequently there is still much work to do so that it is considered a complete product.
It is not a Google Photos replacement yet but it is the closest of all other services I tested.
When you switch to #docker you will never want to boo back. It may be hard at the beginning but it is worth to do it.
You can migrate your services one by one. Docker is just another software in your server.
Main drawback of docker is that images and containers consume significantly more space, but SSD cost is cheap nowadays.
My advise when you learn docker is that you focus on docker compose.