What kind of playlists? Sonos / Imported / Music service playlists?

Sonos have never supported user sorting of anything. Additionally they need the data to sort anything, and if the creation date isn’t stored then no sorting is possible by anything.

Sonos playlists have never stored a creation date, they are displayed alphabetically. (Caveat: my playlists have never actually shown up in the new app or the web app, so I assume that is still true).

spotify!

Oh, well that’s on Spotify then, only they have access to “date created” for their playlists.