You are allowed access the non-Schengen lounge even for a Schengen flight, if you are connecting from a non-Schengen flight (I've done it also on separate tickets). Pre-Covid they wanted to see also the boarding pass of you arriving flight to verify it, but the previous time I did it about two weeks ago the dragon said "I don't need to see that" when I tried offering the boarding pass of my JFK - HEL flight.

The non-Schengen business lounge has had champagne (Joseph Perrier) since the current lounge opened in late 2019 (although it has been closed for the most of the time after the opening).