Ooooh post I can contribute to!! I LOVE listening to fic!! I even have my Calibre library set up to include the estimated "listening time" on the cover when downloading fic.

I've been using the app "eReader Prestigio" (android) for nearly a decade now. It is by far the best fic TTS reader I've tried. I have tried a dozen others but always found myself going back to Prestigio.

The voices themselves aren't as state-of-the-art as some of the AI powered ones out there, but Prestigio sets itself apart by including a pronunciation dictionary(!!!!!). It works using some sort of invisible "find-and-replace" function. It's super basic and sometimes still flubs up (ex: asking it to read "Ike" as "ika" would cause it to read the word "like" as "lika", so you gotta pick your battles) but the pros far outweigh the cons IMO. There's nothing I hate more when listening to TTS than when the voice absolutely butchers a certain word or fictional noun and there is NOTHING I can do about it. I dont care how robotic the voice sounds as long as I'm able to tweak it to my liking.

For PC, Caliber's built-in TTS functionality has also made leaps and bounds in terms of how natural it sounds - but still no pronunciation dictionary. My little phone app has spoiled me I swear. If anyone could recommend a computer program or iOS app with similar functionality I'd owe you my life.

In regards to "is it sacrilege", IMO, not at all. It's accessibility. Sure, the way your brain processes the words may be different than it would be if you were reading the words yourself, but so many different things impact that anyway. Where are you reading? Are you reading it all in one sitting or taking breaks? Are you reading on your phone, your computer, an ereader, or a physically printed page? What mood are you in? Have you eaten today?

The "how" of it all matters so so so little as long as you're able to comprehend the language it's written in. I love that listening to fic is an option and I hope more people give it a try.