Of course there’s no pill to cure delusional malignant narcissism. Consider, what if there was and Trump agreed to take it? He would have looked to the long term and planned for another presidential campaign instead of trying to negate the one he lost. Like the frog and scorpian fable with the frog representing a good chance to win a second term, Trump sunk that chance and and may have drowned it because as a delusional malignant narcissist he stung the frog because it was in his nature.
Obviously there would have been no attempted coup and Jan. 6th wouldn’t have happened. There would have been no House committee to investigate it. I think he would have been a shoo-in for the Republican nomination. Republican’s like DeSantis currently running as sane fascists and culture warriors who have distanced themselves from the unhinged ex-president who seems more and more unmoored from reality every day would have a very difficult time running against a dignified very popular former president who had taken his loss with class.
Whether nominee Trump could prevail against President Biden would depend on the kind of campaigns each of them ran and what was going on in the country from the state of the economy to who was winning the culture wars.