Disagree. People said the same in 2016. I even saw some who thought he was secretly working with the Clintons. Trump got to this point by pretending he's "one of us", speaking about issues in a very simple and blunt manner, and bitter meanness. The name-calling, the weird racial stuff, the hatred of other countries (most of all our allies), and even suggesting an interviewer must've been on her period because she asked a question he didn't like...that's Donald Trump and there's a segment of the population who loves the show.
He's not trying to lose, that's just Trump. Advisors can't control him, he's going to be angry and mean, it's going to turn people off, and now he's facing a younger woman and the best he's got so far is making Vance follow her around like a creeper as Trump questions how black she is. That's your candidate.