I'm no Democrat and there is no particular reason they'd take advice from me. That said, I just had a tactical insight they could use.
Given recent events, maybe they should accept that whoever they run against Trump is going to lose. Our system more or less requires they run a ticket regardless.
They might as well leave poor foggy old Joe Biden and the cackling floozy Kamala Harris in place as sacrificial place holders. Trump/Vance will roll over them like Sherman taking Georgia, and then the Dims can start fresh in 2028, with no lingering commitment to the hapless Harris.