Sense is plenty fast to catch the grinder - It is specced at a peak 4M samples per sec, though I don’t know how that is divided between the up to 6 different values being measured (2 main CTs, 2 main voltage, 2 aux CTs, voltage values the same for aux). It’s really more about the grinder waveforms standing out enough and being unique. Take a listen to this video to hear the criteria device On/Of waveforms have to meet for them to be “detected” as a unique device.
As for data augmentation in Sense, the best spoofing path in my mind is using the Kasa smartplug integration and protocol, since that one has some documentation, and actually feeds energy data into a dedicated Sense device.