For me the best app for audio book on Windows 10 is
Media Store. It is a directory music and video player. You can use directory as playlist.
To Use directory as playlist - I put music file ( .mp3 ) in the root of directory:
Apple
- Banana.mp3
- Peache.mp3
- Lemon.mp3
And get:
Apple [Playlist]
- Banana [Song 1]
- Peache [Song 2]
- Lemon [Song 3]
You can download it here.
Media Store - Microsoft Store
https://www.microsoft.com/store/apps/9nqbh9bw9jpx