The problem would be that with the current makeup of the senate, if Harris resigned it would leave the Senate with a 50/50 split, and they can appoint someone all they want but it has to be approved through the senate, and with a 50/50 split it can be strung out forever.
Not 50-50. Susan Collins would happily go along with the scam.
They love making deals in the Senate. How about Thomas resigns for health reasons (he gets to live), Harris moves to Supreme Court (she gets to live and doesn’t have to keep embarrassing herself), Barack is confirmed (50 Ds + Romney, Murkowski, Collins, Graham etc), Biden goes back to the basement (Jill isn’t as powerful as she thinks.)