A police report != a 911 call from a legal standpoint (to my non lawyer knowledge).
But it is the first step if you need a report written.
You can walk to a station and do it in person. That won't be logged in the 911 database.
It really isn’t. Where I am it is a form on a website.
I don't know anything about NYC, but, normally, a police report actually involves the police writing down some names. So, one lives in a high crime area and one notices that the police are no longer around, one has strong incentives not to go on the record about this or that crime.