Does anybody take seriously the hypothesis that Biden is running for reelection to retain the power to pardon for the next four years? He has multiple family members who could find themselves facing an "unregistered foreign agent" charge. Or money laundering, or even RICO.
Five years from now the statute of limitations will have run out on most of the supposed misdeeds. He may be all that stands between prison and himself, his brothers, their spouses, his son, and who knows, maybe even his wife.
It is a heck of a spot for a tired, mentally foggy old dude to find himself in. Especially if he makes the sacrifice, runs ... and loses. Republicans can do lawfare too.