This may sound counterintuitive given that he won the election, but Trump isn't any better at politics than he is at governing. He won the election through a perfect storm of flukes, election interference and Hillary's overconfidence. So no surprise to me that he constantly says things that serve no political purpose or even hurt him. He just has no clue.
Remember that Trump engineered his own "October surprise" by admitting on tape that he deliberately downplayed the seriousness of the Coronavirus. He is not a very bright guy. But he does have enough sycophants and enablers in Congress who no longer care about our democracy.