Be a part of that change. Run for local office and or encourage other progressives around you to do the same
Change quite often starts locally and flows up. Those in the national party very usually come from state offices and work their way up. Make that pool of people as progressive as possible
Make no seat uncontested
Organize in every place you can. Beyond just elections, organize for unions, organize to protest, organize to stand with your community, do not given in to the complacency that the far right wants you to have
Power is not be given freely, you have to fight for it. That fight lives on and is worthwhile. Things will get worse before they can get better. But we can lay the groundwork for the future to be better
You don't think at the very least when Biden was still running that they weren't seriously considering what to do if Trump won?
Even if not, they still have a couple of months before he's sworn in too