And here’s a reminder that if you run a Plex server, there’s an app called Prologue which turns it into a fully fledged audiobook server.
Plex doesn’t natively support things like audiobook bookmarks in m4b files, and tries to just play them straight through like a gigantic 4 hour long music track. But Prologue does support bookmark data. Prologue simply uses Plex’s service to access the files, (because admittedly, Plex is good for letting newbies remotely access their content) and then it ignores Plex’s built-in “lol just play it like music” instructions, and actually parses the files for bookmark data.
As someone who couldn’t get Audiobookshelf to work properly, (something about not being able to access network drives via Docker), Prologue has saved my audiobook library by allowing me to just host it via Plex instead.