I have a few questions for you that should make you think: How big is the US Army? How many of those soldiers would simply go home in such a scenario vs those staying loyal to the government for whatever reason? How many firearms in the US are in private hands?

Tanks, planes etc are for force on force warfare, not asymmetric scenarios like a "government turned evil, we need to rise up"

"obviously" is the weasel word. How about you try to prove your point instead of stating your position as if it is accepted as true.