Adding audiobook from Spotify - only getting first track

I have the music version of this watch and have previously listened to music playlists and podcasts. Since Spotify recently added audiobooks, I downloaded one that I wanted to listen to on my long runs. But when I go to sync Spotify, there’s no option for audiobooks - only podcasts or playlists. I tried putting the book onot its own playlist, but it only downloaded the first track. I tried with a different book but had the same issue. Wondered if it was a space issue and ended up deleting all my other playlists, but tbh at didn’t solve the issue. Any idea what I can do to sort this? Thanks