What's astonishing is ANYONE agrees with or even mildly supports trump, he's a jumped up moron who conned other morons to get him in the White House, likely Russia/China interfered to make it happen as well, if the world woke up and had experts running everything, all would be good with the planet.
A lot of people were getting a crappy deal before. Trump promised change. Clinton promised more of the same, only worse, and grossly insulted everyone who didn't want to vote for them. It's not astonishing that people voted against the status quo that was bad for them and against fashionable irrational prejudice and discrimination and against a candidate who publically and passionately expressed her contempt for them.
Then there's party politics, which is extremely important in a de facto two party state. Anyone who wanted to vote Republican had to vote Trump.
Then there's patriotism and nationalism. Trump appealed to both, Clinton appealed to neither.
Then there's corporatism, which many citizens of the USA perceive (correctly IMO) as a negative thing for them. Clinton is part of it. Trump spoke against it. He may well have been lying, but he made the right noises and that gets votes when the only alternative is definitely on the other side. If you want X and you have to choose between two candidates one of whom speaks in favour of X and the other who says nothing about X but acts against it, your best bet is to vote for the candidate who speaks in favour of X and hope they're not lying.
Basically, Trump at least pretended to give a damn about most Americans. Since Clinton doesn't, he won.
As for his term in office, well, it's not been obviously terrible despite his apparent incompetence in leadership and his definite incompetence in politics. Prior to the pandemic, I thought he'd win the next election. Now, I think he won't. Which might not be fair because the USA is handling the pandemic about as well as most countries, but to some extent it will be associated with his presidency and that will cost him votes.