That's a win win for the SC.
He wins the election, they can say "Whelp, makes no sense to rule on this until he's out of office again" and hope he dies before dick tatering his way into a third term.
He loses the election, they can decide to rule either way depending on how much grease he's got left in his pockets with no worries about repercussions while they also hope he dies.
I can't imagine a ruling in his favor that doesn't give Biden the power to also commit whatever crimes he wants, but then again I'm not creative enough in the "moral degeneracy" department to qualify as a Republican supreme court justice.
They'll probably rule something asinine like "using a phone isn't treason" and, blinders firmly in place, blow right by the actual question.