Map Report

I believe that the the  mapping tool from Juiced can do this.

https://www.juicedtech.com/old-qb-maps

Alternatively, a solution would be to create a summary report of all of your ZIP Codes and use that to populate a new table called ZIP Codes where the key field is the ZIP Code. Then you can make a native Quickbase map from the ZIP Code table rather than from your individual address table. 

Had some kind of automation or pipeline to keep this maintained then you can have a relationship and summarize the number of customer locations so that you have a count for each  ZIP Code.

But I do not believe that the native Maps report as much in the way of hover ability

You could look at using Mapsly with Quickbase — it lets you aggregate clients by ZIP code, show counts per region, and customize pins or color-coded areas. That way you get a clean visual map with rollup metrics instead of hundreds of overlapping pins.