There is a lot fundamentally wrong with the American system - government, judiciary, electoral everything - that a Biden win won't solve. There has to be some kind of backbone after the fact, a willingness to "stack" the Supreme Court, to enact the "nuclear option" and a refusal to engage in the sort of bi-partisan compromising that ruined the chance that was the super-majority. In essence, they would have to play by the same rules as the GOP does. Biden isn't the President to do that, unless he's done a masterful job at throwing up a centrist facade. Perhaps Harris will be, if, like I would hesitantly guess, she'll be put forward in 2024.
But they have to win first. I do think Biden will win, and I also think Trump will crow about voter fraud and use the Supreme Court as a political weapon to try and steal it. I don't know what happens after that. It is quite scary to see the country that prides itself on a history of smooth transition of power being in such a state. It makes me think about 1932 here and how FF taking power for the first time happened with TD's carrying guns in their pockets, how alien it all seems reading it in a history book. But there America is, not all that far away.