My wife is on her way home from a visit to my daughter's place in Gramercy Park Manhattan as I type. She said it was great, but bring a mask... Everyone is wearing them there. Personally, ICNLT, but my wife loves it. All of the restaurants are open, and she felt perfectly safe.
1) Stop in Tiffany's and check it out. People watching there is
and there is a lot of famous stuff right near there.
2) Take the Staten Island Ferry. It's free and you'll get a different perspective of the city.
3) The Intrepid Aircraft Carrier is a great tour. You'll be right in Hell's Kitchen as you walk to it. I have done it, and the Vets who guide you have sailed on it, and are a wealth of knowledge.