Well I should point out I could easily see between high hundreds of thousands and over a million Trump people simply dying because A) a lot of them are old B) Covid which they deny and had 4 years to die from it.
I could also see a million or so being disillusioned with Trump, either Q people who thought he'd do different or people who saw something else in him that he didn't live up in his new campaigning. Also a lot easier to just check the box to re-elect the president for a certain amount of Americans who may not even be consistent Republicans but just people who thought he did a good enough job giving them free money during Covid and deserved to continue. So those numbers are if anything low and suggest IMO he probably gained some voters as well between losing people to dying and disillusionment and such.
So then the discussion must go towards those Democratic voters, they must have really alienated them, they must have really lost the enthusiasm and angered them. Sure we can discount a couple million as racists who voted for Biden because he was a white man with ties to anti-busing and crime legislation and KKK leadership but not nearly all of them. There's still a significant chunk, millions and millions you have to account for.
I can see it now. Trump calls in gravy team 6 to break him out, they kill a ton of cops in a firefight while rescuing him, once back at the white house he drone strikes the judge and prosecutor responsible and he spends the next couple years vindictively attacking Democrats and their prosecutors and dismantling the justice department while battering the hell out of NY with federal antagonism that's not really legal further pushing the idea of a breakup of the states into the mainstream. Democrats promise to jail him after he leaves office but he dies days before the election after finishing a Big Mac for dinner and Vance issues a sweeping pardon for Trump's family and associates for all activities to which Democrats tut tut but have to respect the institutions and so go on to face-plant in the next election as well despite it being "the most important election of our lives".