Any features like this in the Sonos app would be the responsibility of the music service, namely Spotify.  Sonos presents any sort results as is from the provider.

Sonos don’t have any idea as to the “date added”, only the provider (eg Spotify) knows that. If you want to sort by that field, ask Spotify.

Aren’t the songs in Spotify playlists always represented in “date added” form - first added on top?

Usually. Although my experience is that Spotify playlists in Sonos show as Custom Order, not necessarily date order. And that can’t, I believe, be changed through the Sonos app. Even if you set a playlist in Spotify by date order, and then save it as another new playlist, it will turn up in Sonos in the original Custom Order.

So I don’t think it’s doable currently. Whose responsibility that is I’m not sure.