That’s a shame - I loved NYC but I can absolutely see why someone wouldn’t. January in NYC is freezing and with a biting cold you don’t get in the U.K.. If that’s not outweighed by some great cultural experiences, it puts a dampener on everything because walking the city isn’t fun when you’re constantly looking for somewhere to get out of the cold. Brits don’t ever tend to need the giant puffa duvet coats New Yorkers wear at this time of year so can be unprepared.
Used to go a lot, but the last time I went was pre-kid, so at least ten years ago when it was the Obama era. The highlights of NYC have always been the museums, ballet, restaurants. If they aren’t really functioning because of the pandemic, I can see it would be a difficult experience. Even good restaurants don’t have the same kind of swish upscale super clean vibe that nice places in say, Boston or California, do - it’s a lot grittier as a place. That used to be part of the charm, but I’m sad to hear the city’s gone downhill recently.
A lot of it depends on local government and the economy and that’s bad right now in the US. If you want a more upscale vibe you could try Boston, even the nice center city parts of Philadelphia (Philadelphia has its own grittiness outside of center city!), DC, Chicago. I think the idea of NYC being terribly plush and expensive is a kind of illusion created by film - even the expensive nice bits of the city are not always super plush the way that bits of London are.
I always find it interesting how the US is a funny mixture of very modern and quite antiquated/old fashioned. If you are used to Europe, there are aspects of the US which are surprisingly unmodern and unsophisticated, even a bit tatty, from the advertising to the shops (there aren’t the same kind of shiny middlebrow chain stores we are used to here, from Boots to Sainsbury’s). And though NYC has great food and restaurants, there’s also plenty of bad ones in the mix too. (Quite a lot of American food is puzzlingly unsophisticated to Europeans - especially the wine, cheese etc, even in NYC, so try other cuisines - there’s great Asian and African food of all varieties in New York). If you aren’t experiencing the great bits of the city to cancel out the bad bits, I imagine you’d feel pretty glum about it.
If open, try the Frick, the Guggenheim, the Morgan library (used to do great cocktails on a Friday in the atrium), MOMA, the Met, forget the shopping, seek out some nice niche bars and restaurants to enjoy. Museum restaurants and cafes are often really nice, reliable, and great for people watching.