My non-expert nightmare take is that Biden stays in but replaces Harris on the ticket with Michelle. That solves the loss of black women vote and allows those who pine for the Obama nostalgia (phony as it is!) to vote D knowing they are really voting for Michelle as Biden won’t / can’t last long as POTUS. The press would go crazy supporting this and the non-engaged WalMart voters would see it as historic. There is certainly precedent for Presidents changing VPs upon their re-election so no one would batt an eye. God help the Republic!!