Welcome to HO, and hope you find multiple boards of interest. You can say hello over here on the introduction thread, and feel free to jump in anywhere else - What’s For Dinner / WFD tends to be the most active daily.
I’ll admit that I’m mostly sorely disappointed by gulab jamun in nyc - they are either too soft, too sweet, or both.
That said, for sweets in Queens I like Maharaja - but only around Diwali, so you’re in luck - just a couple of weeks to go. Their sweets are particularly fresh and India-like then. The rest of the year I skip it.
Rajbhog - diagonally across - is also good, but it depends on freshness. The owner (his son actually these days) is usually there, and quite honest if you ask him what’s fresh. Added benefit of fresh chaat and Gujarati farsan (snacks).
Further out in Queens are Real Usha and Usha (good backstory there) - they are Gujarati sweet and snack caterers with storefronts, and tend to do better than most mithai available elsewhere. But I actually preferred Maharaja’s Diwali stock to theirs (including when they special-order catered a wedding, so the sweets were made-to-order).
You might have some luck - courtesy corona - getting direct/overnight delivery from other places, maybe Edison or Iselin or Jersey city. Sukhadia used to be good, but I haven’t eaten their stuff since they closed their Manhattan shop.
Though as I’ve said on other threads here, I don’t enjoy the indian food in NJ, never mind sweets, because it’s adapted to palates that moved here in the 60s and 70s (and I still want the real thing).