I have my all my playlists structured into a bunch of sub-folders in Spotify. First under three main categories Favs, Vibes, and Eras. Favs has all of my favourite lists either sub-foldered by year or "Top" lists (i.e Spring 2025, Top 50 Songs All Time, etc.) Vibes is split into a bunch of mood subfolders (Heavy, Upbeat, Moody, Slow, Seasonal). And then eras is of course sub-foldered by decade (90's Grunge playlists, etc.). Then I keep one "Record Shelf" folder to dump any albums that I'm currently listening to so they are easy to access. Probably overkill, but I love the structure