Not familiar with nettop in Terminal, but if nettop works well, couldn't a script (or even a macro utility) call it up very regularly, leave it open for a time period of your choosing, and then quit it. Loop this and… ?

I am visualizing a scenario where it is opened and closed frequently enough that it is there often enough for your purposes.


On a Mac since 1984.
Currently: 24" M1 iMac, M2 Pro Mac mini with 27" BenQ monitor, M2 Macbook Air, MacOS 14.x; iPhones, iPods (yes, still) and iPads.