You can apparently trade off 3/4 of your royaltys for a higher placement on the coveted Spotify-owned playlists of different types of ambient music, childrens songs etc. According to the article. But stuff like that is not very transparent I guess..
No, this is just an evidence-free speculative conspiracy theory that is now my new head-canon
There are contracts that have been seen by major news outlets but they have not been confirmed/commented on by Spotify.