Who's even serving on the side of the "corrupt nation state" in this scenario? Good luck ordering American soldiers to fire on Americans over 2A of all things. The whole thing is a fever dream.

...except when the authoritarian regime successfully paints dissenters as enemies of the state.

Do you not think the military itself would faction? Because I'm not convinced it would act in a single way. Generals have defied presidential orders.

We’ve seen it across the world over and over again. Rebellions/Government overthrows that are successful are few and far between. Who do you think puts down the ones that failed? The military.

The Afghan point stands, though it's a common misconception that the North Vietnamese were very poorly armed. The Viet Cong were an insurgency group, but North Vietnam had a traditional army which was relatively well equipped for the era. Including rocket artillery (BM-21), supersonic jet fighters (Mig-21s), surface to air missiles (SA-2), and main battle tanks (Type 59, among others). I definitely wouldn't put their weaponry in the same category as "pea shooters"