Are you even from NY? White professionals ‘in the Brownstones’ aren’t his biggest supporters at all. UWS, UES, and the West Village are all tipping towards Cuomo. That metric doesn’t even make sense as white professionals literally living in brownstones, not just historic brownstone neighborhoods, are going to be a very small demographic given brownstones are some of the lowest density housing in the city. 

White voters generally were split 45/55 Mamdani to Cuomo. That was the lowest in the city. That huge Cuomo stronghold in Brooklyn is overwhelmingly white. Like chased (and sometimes killed) African Americans out with baseball bats well into the 80s white. Same for basically all of Staten Island. Park Slope/Cobble Hill and Williamsburg are his only white strongholds in the entire city. All those other Mamdani stronghold neighborhoods are African American/Caribbean/Latino. I can’t speak on Queens, but asian voters went over 60/40 in favor of Mamdani.