Harris will be the nominee. The Turd will continue to crumble mentally and physically. He'll say and/or do something that will make Biden's debate performance look like a hiccup. That might be when he debates Harris in September, or it might be earlier.
Vance is in the game to be prez, sooner or later. But that can't happen if the Turd loses. So he'll conspire with the RepubliQ to get rid of Trump. Of course, unlike Biden, the Turd would never step aside willingly, so Vance, hillbilly lover of guns, will hire another shooter. And this one won't miss.
Then Vance and Harris will have the most invective-laced contest in American history, with Vance continually attacking Harris's race and gender and Harris pointing out what an extremist tool he is. It'll be epic, regardless of who wins.