Prediction
Things are going to get really weird for the Democrats around their convention.
I think Biden won't agree to step down. He will be angry and defiant at the very idea of stepping down. So just before the convention, the poor old guy will "pass peacefully in his sleep."
At the convention, I predict the Democrat moderates are going to try to put in California's Grabbin' Gruesome, but the Far Left weirdo faction (who must represent over 50% of Democrats now,) are going to demand a more radical nominee. They'll put up Old Bernie again, or one of those annoying "Squad" women.
This is going to lead to violent riots at the convention, with a very negative look in the media for the Dems, and a deep intra-party divide for them to deal with.