Oh, please. Do you know how low his ratings among Republicans was during 2015 and 2016? In the toilet. I can still remember the news, after his remarks about grabbing women by their privates, of the huge number of calls for him to get out of the race -- Republicans calling for their own nominee to get out! But of course, he claimed that "every woman lied" about him. All of them! Imagine that.
No, the principle reason Trump was voted in is because Republicans have been trying to frighten their base into believing their very existence is in danger, and they were looking for a non-establishment anti-hero -- a kind of Robin Hood or Che Guevarra or William Tell and so many others -- to ride in on a white horse and save them. Trump was willing to say things his supporters believed, but other politicians eschewed. By willingly suffering the “establishment’s” opprobrium, as well as its investigations and indictments, Trump came to be seen as the authentic champion of those who felt unrepresented.
Of course, he didn't save them, and he was dumped in 2020, but it is a important feature of human nature that, but then we come to a second important part of human nature: the persistence of preexisting beliefs. People don’t change their minds easily, especially about matters wrapped up with their identities. As cognitive scientist Hugo Mercier concluded upon reviewing a wide range of evidence, “Any message that clashes with our prior beliefs…is overwhelmingly likely to fall on deaf ears.”
In the psycho-logic of his supporters, his indictments and the other attacks on him were a badge of courage, a sign of his willingness to sacrifice for their shared values.
Now Donald Trump is the Republican Party. And he will, if he gets the power, do what he does, and tear the Constitution itself up. And I'll bet even then you won't think ill of him. The cognitive dissonance is simply too deeply ingrained.