Democrats' Hail Mary shot

I don't think Democrats have enough time to replace Let's Go Brandon as their 2024 presidential candidate. They could go all authoritarian and surprise me at the national convention, but it's a long shot that Brandon will step aside voluntarily. But I do see a Hail Mary in their near future that can play out in one of two ways.

If Democrat voters do not trust Let's Go Brandon's ability to serve out a term if he wins there's still a way for Democrats to manage that fear among voters.  At the convention they can have Kamala Harris give an amazing, inspiring speech that energizes Democrat voters.  Probably not going to work, given her abysmal popularity ratings.  But there is one other way the same scenario could play out; replace Harris on the ticket with Newsom or Whitmer and pull the same play.

If Democrat voters see a 'robust' VP, they may still opt for the Let's Go Brandon ticket, knowing that Brandon would be gone shortly after he wins, if he can win.  They could invoke the 25th amendment and try to remove Brandon after a few months.  Even with this approach, they are still highly likely to lose, but if they can bring the margins down far enough to stuff ballot boxes, well...