What if I want to remove a song (or artists, or albums, etc) from my library but still want to keep them in a playlist?
I already know the answer to this, and the answer is really dispopointing. You can't. You have to remove the song/s from your library, which will remove them from all playlists. You then have to put them back in. I find this to be a massive oversight on apple's part. They obviously saw the value of being able to separate one's library from playlists, but then made the concept somewhat dysfunctional by not giving us the ability to remove songs from our library as we please... I can think of a few (time consuming) work arounds, but they're pretty annoying.
iMac 27″, macOS 10.15