There are IoT SIMs available on most major carriers, which are intended for economical occasional low-data usage on large numbers of devices. They're popular in GPSes among other things.

5G is looking to reduce the cost of them further as LPWA is a key part of the standard.

maybe one way to fight this is by finding a way to abuse these SIMs/connections to use a lot of data en masse until they get cut off or dropped altogether.

They can easily be remotely disabled if there's any suspicious activity, ie to any other server than the telemetry backend.

Exactly what I meant, and then you use their own SIM to DoS or DDoS them until they or their network provider disconnect the service.