Comment by KeplerBoy
Don't end to end trained models already do this to some extent? Like raising the pitch towards a question mark, like a human would.
TortoiseTTS has a few examples under prompt engineering on their demo site: https://nonint.com/static/tortoise_v2_examples.html
That's a bit of basic and random. Some models have the features you describe. From the better models you get a slightly different voice for text in quotes.
But the difference to good audio books is that you have * different voices for the narrator and each character * different emotions and/or speed in certain situations.
I guess you could use a LLM to "understand" and annotate an existing book if there's a markup and then use TTS to create an audio book from it and so automate most of the the process.