If we win the senate, Joe Manchin isn't going to be a problem. He's never cast a *deciding* vote against the Democrats, and he's not going to start now. He votes against the Democrats when it's not going to affect the outcome, so he can tell his red state that he votes both ways.
There will be some humdrum legislation that's set to pass with the support of five or six Senate Republicans, and Manchin will decide to arbitrarily vote no on that, just so he has a scorecard of voting both ways. It's what he's always done. Won't change now.