No.
If Biden loses this, it won't be because of "muh Russia", "muh mail", "muh 'lectoral collij", "muh Bernie Bros", or any other pregenerated boilerplate excuse Democrats can and already have wound up. You can guarantee if an excuse for losing comes out of a Democratic strategist's mouth, it's the complete opposite of a true and impartial summation of how the election went down.
It'll be because of shit like embracing the Rick Snyder endorsement in a critical swing state and bellwether, when Biden's already under fire for free trade support. It'll be because his campaign and party actively rejected policy positions supported by nine-tenths of his own party's voters. It'll be because of his highly questionable statements on race during the campaign. It'll be because of running on increasing police funding in the greatest period of racial unrest since...frankly at this point, the Civil War itself. It'll be because Democrats put all their eggs in one basket -- beating Bernie -- and then decided to re-litigate 2016 as their 2020 campaign strategy.