Try starting with something suspense based that does not have convoluted writing and really grabs your attention, like a Dan Brown book or Harry Potter (read by Stephen Fry). Also, go for the professional readings (i.e. not most of Librivox) and pay careful attention to what reviews say about the reader, as their performance is essential for comprehension. Play around with listening speed a bit (both too slow and too fast won’t work, depending on the material). I could easily increase material complexity after getting through suspense-based books.

I could not get into audiobooks (even after years of listening to scientific talk podcasts) until I got hold of Origin by Dan Brown in an Audible trial, and ended up being gripped by the 20 hour book for two weeks straight. It has been 15+ audiobooks from various sources per year for me since then, which has really enriched my life. Retention is better since I finish the books that can be integrated with various activities not requiring verbal thinking way faster.