I looked at the original listing. It’s a COOP. This post explains why the $4k is so high. Unlike a condo the buikding’s mortgage is folded into this. In a coop you own shares in the building not your unit as would be the case in a condo. You’re also paying taxes for the building folded into that. The COOP explains it. This link explains it.
https://www.google.com/amp/s/www.brickunderground.com/buy/why-are-maintenance-fees-so-different-in-nyc-buildings?amp