Data Usage Monitor

Can anyone suggest a good data usage tool for the raspberry pi? Our vendor has moved their software to a cloud based solution which is constantly broadcasting data and I’m wanting to do some testing to see if our current data plans will be sufficient it would be great to have some kind of network monitor that can show me how much data is going through the cellular link.

The firewall counters are a good start but i would like a little more fine tune data that I could sort by IP etc to really get a good look at what is happening.

I’m using the RAK2013 over 50 different systems using a Raspberry Pi 3, 3B+, and 4 depending on when the system was installed. Thanks in advance.