netflow/jflow only generates per interface statistics that are sent to the analysis server.
the reporting engine to corolate and report on things like top talkers is a server function. So if your current server does not have the reporting you are looking for you need to source other ones.
PC world has a convenient list and description of some open source options that you can see if they have the reporting you are looking for.
https://www.pcwdld.com/free-open-source-netflow-analyzers