Someone else here just gave me the opposite answer.
Well, I would have to say, whoever gave you the opposite answer may not know how it works.
The newly elected Congress will be sworn in on January 3, 2021. The electoral votes are scheduled to be opened and counted and certified by Congress on January 6, 2021. That is the basis for my saying that the newly elected Congress would deal with a presidential election, if they need to deal with it. The retiring or defeated members of the old Congress are gone by the time the electoral votes are counted.