Except it wouldnt get to that point unless both candidates fall below the threshold to win. So for example if it was a 269-269 tie then it goes to the House for the vote. They would need to have a lot of states de-certify to get to a point where Biden doesn't have the majority and by then you are talking Civil War anyways.
If Michigan just holds off they either dont send electors at all (which lowers the threshold) or both sides do and it becomes a Constitutional Crisis and the smart money is on President Pelosi.
To better explain what I mean...lets say all states certify but Pennsylvania. PA decides not to send electors instead of sending what will amount to 2 sets. (which is how it would play out) You would subtract 20 votes from the Electoral total (538-20 = 518) and it is now 260 to win instead of 270 to win. Biden still has over 260 so Biden still wins. They would need to eliminate enough states to get Biden's total down to 232 or less to force a House vote.
(note: I am not an electoral scholar this is based on what I have read, what lawyers have said, what election experts have intimated and what has happened in the past based on my 2-3 months of study on this in the wake of where we were headed. I could be way wrong and if I so I will of course admit it)