Install such trackers on each PC and then collect that on your PC for a report.
I have a TP-Link Archer C9, which is a dual router, 2.4ghz/5ghz.
There are 6 devices connected to it. 3 to 2.4ghz, 2 to 5ghz and 1 hardwire connected.
Is there a way/program that will track each one and let me know its total data usage?