Turn their power off.
Your point is valid. “The U. S. Army is incapable of operating in mega cities.” Wrong.
It may be incapable of holding and governing said cities, at least within rules of engagement that are currently acceptable to the delicate sensibilities of our effete leadership. But siege has reduced even the hardest targets since the Bronze Age.
And the Air Force can always operate OVER said mega-targets.
We also need to get over the idea that if we break it, we bought it, i.e. We need to pay to rebuild these crap holes after we make their rubble bounce around.