When you import your define a directory structure of your choosing. All the files are accessible in their regular format.

If you’re talking about the ability to index another directory they are experimenting with a read only import (as opposed to upload) now.

Have you checked out Immich?

It doesn’t have photo editing but it’s got apps w / backup for your mobile devices and a web interface. Multiple album creation with sharing outside the app etc. Doesn’t hit everything on your list but it’s close and it’s been awesome for me so far.

Use the archive?

deb http://archive.debian.org/debian/ stretch main contrib non-free deb http://archive.debian.org/debian/ stretch-proposed-updates main contrib non-free deb http://archive.debian.org/debian-security stretch/updates main contrib non-free

I gotta ask though, why?