an interesting idea, but she would not get confirmation from the current senate composition. the 47 democrats and 4 independents would all have to agree on this and then follow through. sinema and manchin are part of that 51. republicans and some others would claim that harris cannot tiebreak a vote for her own confirmation, so that 51 is needed and would have to remain united.
it's way to risky of a gamble, the vacancy would have to exist before it could be filled. all it would take is one senator to change their tune. you'd just be giving the diaper his next seat before he even gets a chance to lie his way through the oath of office.