The hotels I know of with rooftops pretty much all have bars or restaurants of some sort. Some are more raucous than others, but I'm not sure any of them would really be described as "quiet." Generally if a hotel has an accessible roof with a view, they're going to want to monetize it with food and beverage.

If you're just looking to avoid party music and waiters pushing you to order stuff, but don't mind being around a lot of people, some of the outdoor observation decks might fit the bill. Top of the Rock, the Empire State Building, and the Edge all have outdoor spaces with spectacular views. I've been to the Edge most recently and there were lots of people, but it was still possible to stake out some space and just chill for a while, and the views are spectacular. To up the adventure level a bit, they also offer the City Climb, which looks pretty spectacular if you don't find it too terrifying. But you'll still be in a group and won't exactly be able to linger up there.

If you really want an outdoor view all to yourself, I'd look for a tall hotel with a balcony. But expect to spend some serious money to make the most spectacular spaces your own for the night. Here are a few: https://www.cntraveler.com/gallery/hotels-balcony-nyc