I don't understand the 'constitutional crisis' part, if the voters elect Biden knowing what they will already know in November then so be it. A presidential candidate should not be above the law, however dishonestly it is applied. Even if an ex-president candidate is the Accused. If there is a miscarriage of justice and the voters allow it to influence their vote, then that is the way it goes. IOW, you get the gov't you deserve. I don't see how the Constitution or any law can address the misuse of our justice system.
The same reason why voters said if they had know the truth about the Hunter laptop, it would have changed their vote. Suppressing that information was election interference.