Your entire post ignores the reality of what urban small arms warfare looks like. Look at the hellish time militaries have in urban settings: Fallujah, Kabul, Aleppo, Gaza City. Yes, militaries are way better than regular civilians, but there’s something like 400 million guns in the US. This isn’t just a few people we’re talking about here. If 1% of the population puts up a half decent resistance there’s going to be a hell of a fight.