Thanks for mentioning audiobookshelf. I'd totally given up on using jellyfin for audiobooks. It just absolutely butchers any book split into multiple files, which is basically all of them.

I'll give audiobookshelf a look!

You're welcome. The Android app is pretty good, but for iOS it remains unreleased, so you have to deploy yourself. Prologue seems to be the best iOS App.

There are other unofficial Clients (e.g. in flutter), but I tend to use audiobookshelf as streaming player paired with vlc to play downloaded offline files (the app is not so great here)