Ok I’m not even American so I won’t be voting anyway. With that out the way I feel like Biden would be better for the left. Why? Because liberals wouldn’t be able to blame everything on Trump and be smug as fuck. Shit is going down and while the Republicans are in power liberals can pretend that everything thing would be jolly under their presidency. If Biden is president and things are still going to shit the left can actually attack liberalism properly.
Problems with this view?
I don't think there's anything wrong with your analysis per se. If Biden wins, he will accomplish absolutely nothing. Material conditions for the working classes will continue to seriously deteriorate which will in turn lead to more support for the left. However, what will also happen is that a whole lot of Americans will see Biden as the best response that liberals and the left (since they lump us together) had to things getting worse, and they will instead heartily embrace fascism from someone on the right who is actually competent. I think the later will be a much larger number of people than the former, though.