A king undermines the concept of a republican party.

These are all just name tags anyway. Republicans aren't any more pro-Republicanism than Democrats are pro-Democracy. Hell, even the Libertarians aren't particularly libertarian, unless you take that crap about Anarcho-Capitalism at the most superficial face value.

Trump literally tried to go against governmental policy.

Sure. But he's allowed to do that if you just assert the government policy was wrong/illegal/bad. That's one of the fundamental problems with bland legalism. Any lawyer worth their salt can argue both ends of a case convincingly and lots of the appellate court judges are political creatures who only hear what their paymasters tell them to.

you even included the part where he admits the joke

Bush put "Unitary Executive" in the American political lexicon. If he was joking, he certainly didn't act like it.