As many others have stated and voted up, the playlist folder organization has left much to be desired for a long while, but is especially frustrating now that the desktop UI and mobile UI, especially, are so frustrating to use. I have made and followed many hundreds of playlists and organize them into folders based on year (the ones I make) and mood (from friends, venues, Spotify, others). It's so frustrating to have to drag and drop these in the tiny window on the left of the screen, which doesn't respond appropriately to a trackpad. It's infuriating this is my only option to reorganize my music library, as there's no way moving playlists into folders at all in the iOS app or by selecting a folder through the three-dot menu. It's even more frustrating that these folders aren't even visible on the Playlists tab, or there isn't a separate Folders tab, and there's no way of visually distinguishing between them because you can't customize the cover. Between many other similar frustrations raised here about the recent UI release and issues about the echo chamber of music, I'm strongly considering just pulling a scorched earth policy on my 8 years of premium membership and moving back to a different platform, as discovering and organizing music in the early 2000s was less aggravating.