Now would be a good time to be collabing with Biden on adopting various virus related policy ideas. The thought of dems winning the senate and having Bernie and Warren heavily influencing a Biden admin's first stimulus bill should have liberals wet. You won't get everything you want (I'm assuming dems won't be close to 60 votes) but a dem house, president, and senate would get most of what they want in this situation.
I'm not sure who Biden is intellectually. He's never struck me as smart or thoughtful on policy, and instead kinda just existed in the senate. On foreign policy he was more intellectual but often wrong (Iraq). I'm not shytting on him, I'm gonna vote for him with zero reservations...but my point is that he is a president who can be molded by the legislative branch. Similar to Trump in the sense that he'll have his pet policies and directives here or there but I don't see Biden being a major obstacle to short term change. He's gonna have to come out the gate swinging in those first 100 days, and that means a major stimulus bill and beefing up Obamacare (return full funding, public option, etc). I'd imagine those things will consume his first term, but maybe he moves on free community college and infrastructure. A lot of spending. Driven by Pelosi in the House, with the opportunity for Warren and Sanders to dominate influence in the senate.
If you're a leftist that should be your main interest right now. Win as many seats in the House or senate as you can and start going to work, because Biden's time is gonna be forced entirely on fixing this mess and getting re-elected...which means spending a LOT of money.