Actually, this legally can't happen. If a Senator and a Congressman contest a vote, it goes back to each house and both the Senate and the House have to agree that something is wrong with the electoral vote. Of course no one is contenting that anything is wrong with the certified electoral vote. The House and Senate can not legally object to anything outside of the electoral vote. If they find massive fraud in the popular vote, that is not even grounds for contesting the vote. All Congress is doing is certifying the Electoral Vote, which has nothing to do with how the states ran their elections. Anyone who thinks they can overturn the election has no understanding the system. Even if both houses weren't controlled by the GOP, they would have no legal grounds.
Yeah but, they could then use that to say the Congress decided to vote him in and would not take the time to investigate. I doubt any Senator in their right mind would stand up!