I imagine a pipeline between Calibre-Web[0] and audiobookshelf[1] going through Abogen, where Calibre-Web supplies the books, Abogen generates the audio version of it, and Audiobookshelf serves them. Great solution for the hearing impaired.

[0] https://github.com/janeczku/calibre-web

[1] https://github.com/advplyr/audiobookshelf