The only way forward is as follows:

1. 25th Biden. He’s clearly not stepping down.
2. Allow Kamala to succeed as President. This way the keep all the campaign money raised.
3. Barack agrees to serve as VP.

This would unfortunately be a winning ticket IMO and is completely allowable under the 25th amendment.

From Dr. Google: “In fact, the relevant constitutional provisions, their histories, and their purposes all point to the same conclusion: A twice-before-elected President may become Vice-President either through appointment or through election and — like any other Vice-President — may thereafter succeed from that office to the Presidency “