If you have anything on your network (like PiHole or a router feature) that filters out connections to certain internet domains, that can prevent new features from showing in the app.

See the following: Sonos & Pi-hole

Checked the app yesterday and now the play button now has the new functionality, strange.

In recent months, running the latest app and firmware versions is no longer guaranteed to have all features available in the app.

Sonos now flag users for certain features which are rolled out to users at random.

There is no way to know if your account has been flagged for a specific feature or if another issue is preventing the feature from showing.

Which makes diagnosis near impossible for normal users.