I have the same problem with my wallpaper.
No, you can force it to use one player but not two, to force a single player select it from the app settings
You can try this in the visibility formula:
$if(mi(package)!=com.spotify.music,NEVER,ALWAYS)$
I know you can limit the preferred players now and SoundCloud and Spotify are on that list.
In the app menu, Settings > General Settings > Preferred music player