I tried Calibre web and Kogma.

Calibre is just bad software at this point, it’s clunky and not really designed as a server.

Kogma was fine, but a web only interface made it hit or miss. The big selling point for me with audio bookshelf was the ability to download local copies.

Oh yeah, the multiple libraries is a good point!

You can read using the web client or dedicated apps (android and ios). I feel like the clients work just as good if not better than similar software.

I haven’t tested how it handles two versions (audio/ebook) of the same book, but I have ebooks and audio books and it works well for me.

The only real downside I’ve run into is it’s very opinionated about folder structures around authors.

The one I’ve enjoyed the most is https://www.audiobookshelf.org/, it may be “focused” on audio books, but works really well for everything. It also supports offline mode (meaning downloading local copies in the app).