Information control is tight in the military when deployed, especially when coming down to the enlisted, it may not matter how they lean politically, in a scenario of break down of established order if they can be convinced they fighting an enemy, they will, and it won't matter if they are waving the Gadsden flag or not.
I was watching one of the youtubers who was former special forces, and he made pretty good point. If we use modeling on our civil war with how the govt worked on the war on terror when it came quasi legal orders and strategies, even if military at large may balk and be unreliable, their use of PMCs will be relied on heavily, and there will be enough tier one warriors that are not in service but working as PMCs that will take contracts to eliminate insurrectionists for the money offered, and they won't care if its Americans or not, and its those who will be deployed against groups of resistance rather than military.
Still, we know that nobody is truly certain of the future or how things will go and a lot of things have to remain static for many of these predictive scenarios to play out, and that probably not going to happen. Every unforeseen factor that comes into play will cascade to collapse preconceived scenarios. Things like a chocolate shortage may make even me genocidal if its due to some skittles eating "taste the rainbow" leftist.