since it appears you got an answer, I want to ask the opposite. I want to have audio of a book to listen along to where I can just plug in an ebook file and it the little robot in my device starts yappin’

All the websites are either 5000 character limit, paid AI, or Microsoft SoftwareAutomaticMouth (SAM) from the 80s that you can hardly understand (fun to make swear though)

Funny, I worked on this 2 days ago.

Just use Whisper. I chose Whisper-GUI by Pikurrot

Also the Linux app SpeechNote from Flathub provides a nice GUI for STT, TTS, and machine translation, all in one.