I know it sucks but in the worst case if you really need a quick fix, Android ebooks readers like “fullreader” will read your existing ebooks through the android TTS
I tried searching for another app using better quality voices (some do use amazing AI voices) but they’re of course not free and I couldn’t find a working cracked version as they use a remote server for the AI
It lacks the tones and quality of a real voice actor, but until you find a reliable source…