On the bottom of the linked page there's the said news below. 😟 Having the same issue. I am a 'full-album' listener, but I have a real bunch of playlists too and I'd like to separate them like that.
Mac How To Delete Applications
Move songs from My Music to a playlist
If you have songs in My Music that you want to move to a playlist and remove from iCloud Music Library, you first need to delete the song from your library, which will remove it from all playlists. Then, add the song back from the Apple Music catalog and add it just to a playlist.
How To Delete Music From Itunes Library On Mac
Dec 14, 2018 With over 45 million songs, Apple Music is among the richest music streaming services out there. IOS users can find virtually any song they’re looking for and add it to their library. As a result, it wouldn’t come as a surprise if your Apple Music library gets cluttered with time.