The people who believe that believe that every US President is appointed by God. This is a very common Christian view and there’s nothing special about Trump in this regard. By the same token, Biden and Obama were also.
It’s an interesting subject.
They should. I'm not sure that they all do.
Around Trump's inauguration, I heard people making the "Trump appointed by God" statement as if he were uniquely appointed by God - as if he was different from Biden and Obama.
Now, that's not Christian theology. The Christian position is as you stated. And second, the "Trump uniquely" thing is (almost certainly) not the position everybody who believes or says that Trump was appointed by God. But the prominent people, the ones being quoted, sure sounded like they believed "Trump uniquely", which is a distinctly non-Christian position.
I believe there are two scenarios possible. Your kindergarten teacher and D.J. Trump (and Obama, et al) were all appointed in their roles by God.
Or neither.
I don't think the president is one bit more important or special than any of the teachers I've had. I know he does think so, but that's his business, not mine.