PRTG has a Netflow sensor, which makes it possible to transform it into a Netflow server so that network flows can be analyzed.
Before configuring the sensor, you must set the network equipment to send the streams to PRTG.
Netflow sensors can help you analyze all the traffic on your network. To have relevant data, I advise you to set up this type of sensor on a core network or a firewall.
It can also be put on end switches to do an audit.