Trump may offer a pardon for him not Hunter if he does not resign, after all Mondale in 1981, Gore in 2001, and Quayle in a VP case in 1993 presided over their defeats. But Kami cant?
Harris could refuse to preside, in which case the President Pro-Tempore would preside , which would be Grassley
Don’t forget Nixon in 1961 - he directly lost the race for the Presidency, like Harris, but EVERYONE knew that Joe Kennedy had the election rigged. Nonetheless, Nixon sucked it up and decided not to challenge the outcome, as he was a true patriot who didn’t want the country divided in the middle of the Cold War.