Looks like you can hit the three dots next to “library” and then delete all downloads! 
Discussion
Yeah, But it doesnt do anything. Mine is still 20gb
Yeah, it doesn’t clean shit.
Are you sure? For me it removed the downloads (but left the episodes showing in my library - playable over WiFi/data but not downloaded to the device).
Try tapping the home button (bottom left) then profile icon (top left) then settings > library and disable auto-downloads. Then also try the “re-sync” button at the bottom. Worth a shot 🫡 
Yeah, those functions do nothing. Still 21.54gb on my phone