I'm not a New Yorker, but a New York food person I follow has a small rant about how people obsess about the best NYC slice, but that the real point of NYC pizza is that it's available everywhere in the city, like that you are never far from a good NYC slice --- so that the idea of seeking out particular slices kind of misses the point. NYC'ers: how bad is that take? (None of this is to say that it's illegitimate for…
I'd go as for to say that looking for "the best" NYC pizza is not what you want to do (at least, not for your first NY pizza slice!). Experience just how good an average slice is; if you're not blown-away, at least it's not "the best" and the disappointment won't be as great.
One last point is that "the best" might refer to something very specific. Atop many "best pizza (in the US)" lists is Frank Pepe's in New Haven, CT. While their pizza is very good, nearly every writeup is specifically talking about their white clam pie.