His performance may have drawn some gasps from the audience, but I doubt it had the same effect on his fan base. He was not there to speak to the US as a whole; he was there to speak to his die hard supporters - those who actually enjoy his racist, sexist, hateful remarks and voted for him in 2016 because of them; the same people who were willing to stage a coup in his favour in 2021, after four years of ignorance, pettiness and hatred.
His strategy against Biden was winning because it gathered him bipartisan support - even Democrats were dubious about Biden being able to do a good job - but now that that’s out of the question, Trump has fallen back to his usual script, because it’s too late to do anything else. After all, questioning Obama’s birth and throwing sexist remarks against Clinton won him an election; why wouldn’t it work again? Just stick to the fanbase that won you an election once and almost won you another the second time, and hope for the best.