I do not know....
On one hand Biden performed poorly and in a more traditional match up, he would drop a lot, but here I suspect many are choosing because they fear of the other candidate.
So, if you truly believe trump is an existential threat to our Democracy and our way of self governance, what are you going to do if Biden is incompetent. You are not going to vote Trump...
I have no idea what the collective consciousness is going to come up with.
Personally I am in the same position, I am reluctantly voting Biden. I am not one of the few undecided voters, and what is important is how will they react.