I have said it before. Once you decide to take down the king, you had better succeed or you are going to die trying. This could turn into a monumental political bloodbath if Biden remains resolute.
It could be that Hunter Biden is the main sticking point. Hunter faces a new trial on tax fraud in September, and Biden will want to pardon him if he is convicted. But Biden can't do it until after the election, for obvious reasons. Bowing out now might mean a jail term for Hunter, and I doubt that is something Biden will ever accept.