China dervies a ton of authority and Legitmacy from the PLA (peoples liberation army) and Russia is run by from Inteligence service members of the KGB low level ones to be sure but I don't see how China and Russia are counter examples. The US isn't their yet we will see if the backslide happens in the next two years but I think its of a different qualia than we see in the "typical" Authorithian State.

Ironically I was watching Nuremberg last not and is is schocking how close some of the leaders of this country are to characters like Hermann Göring, or Hitler himself in talking points. They are certainly populists but the language they used is MGGA (make german great again) so to speak. And factually that were not particular that good at it either most of Germans recovery is really due to the liberal government that pass laws that built the Autobahn were laws not by the Nazi party. They certain jumped on them and accelerate them but effective governence is not really for the populist

A military coup in the U.S. is imaginable, which probably explains some of the top brass purges (until recently, where it's probably an attempt to deflect blame for the massive Iran fuck up).

Putin did it better; he kept the military weak and aggressively managed the risk via the FSB.