I'm A1 in French and got there primarily with Duolingo, a little Pimsleur... and lots of beginner audiobooks. Also a fan of RFI's "Easy French Newspaper" daily podcast, but yeah, it would be so much more interesting to have a tech-focused version of the concept.

On that note, another suggestion: Offering a mobile-friendly readable transcript to go along with the audio. (RFI does this.) Reading along with the audio is my preferred way to "listen" to French audiobooks.

Also, presenting the transcript in a readable form is another way to gate content behind a log in and/or upsell. Of course, yeah, would rather it all be free, but your costs are real!