Wow. This is awesome! Seems like a lot of work has been put into building this. Nice design.
Definitely a product "For those who are obsessed with personal growth."
Have you ever considered building a social aspect too? (i.e. connecting your account to X to see who else from your contact list uses the app and let them see what you want to achieve)
A lot of times we actually have authors narrating their own content. We've created a platform where any writer can come and request his articles to be turned into audio. This can then be added as an embedded player at the top of their posts (https://www.listle.io/writers). These articles get sent to our narrators who record them. They're then forwarded to the authors as a code snippet which they copy / paste on their stories.
We're very much focused on on-boarding smaller writers and the content is most often evergreen, with some news, but the type that doesn't expire the next day.
Every article is still owned by its author and credit is given to each of them. If you tap on the author name, it redirects you to the original post. We're currently in the process of making partnerships with several more authors. For our current writers, we offer embedded players for their Medium page / blog and in turn, host their content on Listle.