Spotify should have a customizable feature for a public playlist. If I find a public playlist, I would like to customize it and build it in my own personal image. Add or remove songs at my will
Updated on 2018-11-15
You can create a duplicate of any playlist, which you can edit to your liking. In the Desktop app, click Ctrl - A within the playlist you want to copy to select all the tracks.
Next, right click and Add to playlist should appear. You can add them to an existing playlist, or create a new one.
Hope it helps. :)