Reddit mentions of The Witness for the Prosecution

Yes. This is called Whispersync.

Your best bet is to start on the Amazon side. Search their Kindle books for "Whispersync enabled" - I think it's a checkbox in their search engine. Actually, there's a link to a restricted selection of eBooks with Audible. That's the same thing.

From there you can make your selection. There's a top menu selection for "Classics for $0.99." Obviously, I'd start there since this can get expensive if you're in it for the long haul. I do think you will need an Audible account to take advantage of the Whispersync "deals". Though you could always pay full price. Since this is a "rehab" expense, perhaps you could even put it on your deductions in next year's tax return if you itemize. You may also need a Prime account. That's not cheap, but I honestly don't know how I would live without it in this modern age. (shill, shill, shill)

The only problem with those classics I mentioned above is that you'll also be able to find them for free on librivox. But the narration quality is probably not as good as you need and they certainly won't have an app that links the text with the reading.

If you already own any eBooks, there's a link to "Add Audible narration to books you own." That will look through your personal ebook library and give you an add-on price for the narration. It may be good to start with a text you have already read and this would be the way to do it.

There's also a link further down on the menu to "Add narration for $3.99 or less." Obviously, that's going to be the biggest bang for your buck.

And using all those search methods, I stumbled across this:

Witness for the Prosecution by Agatha Christie. Kindle book for $0.99, add narration for $3.19. Though upon further inspection, that's a short story, not a full novel. It may not be as good a deal as it seems.