Does that make him fit for the most serious job on earth? Well, there's a part of Trump's base that would rather have someone unprofessional, because it means that he's taking shots at "the system." Basically, if the media and the Democrats hate him, he must be doing something right.
I get that this is how they think, and I thinks it's absurd. But rather than just call people names I'm trying to gain a better understanding by forever assuming I'm the one who doesn't get it. What I get instead is just affirmation that people are ignorant and/or delusional.
What you just described is exactly the TDS that people accuse the left of. If you inherited a fortune 500 company would your metric for who should run the company be that he's a total asshole who insults people, and would you deem unprofessionalism a must? No sane rational person would, and the funny thing is that to the vast majority of Trump voters they know this because they wouldn't accept that in anyone else either.
But for some reason Trump gets a pass. Trump doesn't live by the rules that apply to everyone else in America, in fact for Trump those rules are entirely backwards. The things everyone likes about him are the things that are considered disqualifying for anyone else.
JD Vance is a great example of this. At the debate he refused to answer whether Trump lost, he has been stuck having to answer for it ever since. See Vance doesn't get the pass Trump does, he doesn't get to pretend to be a complete imbecile, he doesn't get to just lie in a way that isn't remotely believable even to MAGA. So why does Trump? What is it about this man?