Thanks. I tried this a few different ways also, but it also needs the iPhone and iPad apps published on App Store, web server to sync across devices, and other things. I don't think that was solved in the ChatGPT you linked.
Thanks for the suggestion but Voicedream is garbage. There's no pagination for books so it's a massive, scrollable doc when I upload an ePub. Even worse, the TTS sounds like it's from the 90s and doesn't have the latest human sounding voices that OpenAI has.