Of course, adding music to a playlist broke a couple of updates down the line and, as far as I'm aware, still doesn't work properly several years later.
(I moved to Marvis Pro[0] because it has reasonably complex smart playlists that just about mimic what I was doing with my generator except they're transient and not saved as mine were. Win some, lose some.)
[0] No link, sorry, because it'd either be iOS App Store or ad-laden bloat sites "reviewing" it. https://www.reddit.com/r/MarvisApp/ might be worth a read though.