Their first targets would be things like power plants, tv stations, and central network nodes. Sowing chaos is useful, sorta, but that means things are still usable -- and the OpFor can potentially hit back. Better off just silencing the wires altogether; hit the power plants, tv and radio stations, major telephone & data centers, undersea cables, etc.

If I had $40B to budget on cyber warfare I'm finding out how to hack nuclear plants or cause hydroelectric dam overloads, not tinker with the Amazon accounts of the flyover states.