At the end of the day, Biden is going to be POTUS IMO. You can say the Democrats cheated, but it's going to be impossible to prove, even if they did.
What they DID do, was put together a damn good game plan; build a WAVE of mail-in balloting, hold those ballots until the Red vote was in, and then close up shop and erase those leads.
Chalk it up to a perfect storm. I don't think, in a conventional election, that Biden wins, but it is what it is.
Just be thankful that the Republicans gained in the house, and are going to keep control of the Senate, which will hopefully limit the damage that Slow Joe can do.