I'm working on a tool to remix/manage my playlists, that's agnostic from the different music platforms.
I used to have an integration in Spotify, that automatically copied my "Discover weekly" playlist into an archive. Over time, it grew close to 10000 songs. It also started to get polluted by ambient sound and kids songs when my daughter was born.
I wanted to clean it up but as far as I could tell, the only way was to do it manually, song by song. I'd want to have something more powerful, that would easily let me rearrange/split/curate my playlists based on any arbitrary constraint.