The top brass of the military would not have supported a coup by Trump and the group that protested that day was not large enough to effect regime change.
I certainly am not confident in your claim. And if the military had stepped in to prevent a federal coup, I think America would have fragmented into several state coalitions. In all cases, the nation has been badly harmed by the rioters and the insurrectionists that led them. Indeed, we’ve yet to see whether the US remains a democracy: several states are doing all they can to dissuade and prevent citizens from voting, or gerrymandering the districts. It’s a knife’s edge now; the country could easily fall to authoritarianism.