Random musings:

The spa is insanely expensive, but they use La Prairie products, which are, well, also insanely expensive. If you want to go to a spa that's still luxurious, but more reasonably priced check out Great Jones Spa or Aire Ancient Baths. If you want to go completely out of the box, Spa Castle in Queens is a fun half day trip (and near some of the best Chinese food in NYC).

Food in the area is not great. It is more of a business/rich people area with no taste.
My few recs are (super cheap and super expensive):
Land of Plenty
Burger Joint
The Grill
The Pool
Pizzarte
Todd English Food Hall (specifically Luke's Lobster and Lady M for the crepe cake)
Empellon
Vaucluse
Daniel
Rotisserie Georgette
Yakitori Totto
Benoit
Vaucluse
Daniel

Honestly, I recommend hopping on the subway downtown for more solid food choices. It is only 10/15 minutes from where you are.

Activities:
You're not into Museums, but MoMA always has something interesting going on that is outside the box. Right now there is a fashion exhibit that I've been meaning to check out.

Central Park is obviously beautiful. Perhaps ice skating at Wollman Rink?

You say you're not into theater, but how about more modern theater? Dear Evan Hansen, Hamilton and Book of Mormon are definitely breaking genre norms.

Maybe check out a Brooklyn Nets game? You can walk up and down Smith and Court Streets beforehand for some pretty nice indie shopping. Most of the stores close around 7.