This might be debatable. It's not like voters left Trump in droves. He got even more votes in 2020 than in 2016.People didn’t vote for Biden because they loved him, they voted for him because he’s not Trump. It’s not that they were the “dream team,” it’s that they were literally anyone except Trump. You could have put “non-Trump candidate to be named later” and they probably still would have won. Because people didn’t want Biden, they wanted anyone except Trump...
In the end even more votes turned up for Biden. New votes. An unbelievable 120yr record in voter turnout. Mostly by mail. Many without any proof of identity.
Might be legit, might be ballot stuffing. I'd like to see a thorough independent audit before I ever believe it was an honest/fair win.