1. The time to do that was BEFORE the electoral vote formalities were done in the states in mid-December 2020 (December 14th, I believe).
2. The inauguration date is established as January 20th. There was no way in hell any kind of investigation could have been done in two weeks. It was at least a year and a half before even a single jurisdiction completed its own audit of the 2020 voting.
Have to agree with your points about timing.
Once there was some headway then the last minute acceptance of the outcome would have had reason to be delayed such as whether a judge sided with Bush or Gore over the Florida recounts.
That was why the Left made up silly Office of the President Elect of the United States of America signs and stage sets for photo ops to convince people to give up. There never was such an “office.”