While not the perfect answer to your question, I recently freed my entire Audible library from its DRM shackles via https://getlibation.com/ and set up https://www.audiobookshelf.org/ to host then on my server.
That process was so ridiculously quick and simple that I don't know why I didn't do it much earlier. Migration with full and flawless metadata was as easy as copying the files in the right folder.
Audiobookshelf offers all the benefits of a cloud based player like Audible, with cross device sync and ubiquitous availability. Heck, the library and players work better even. And, if course, there's full control over the data.
Now that I am hosting my own audiobook library I'm far less picky about where I get them.