A lot of states passed legislation for non partisan redistricting in the 2018 midterms. That means much of gerrymandering will be undone next year when the census results come in. That's a big part of the hard reset.
In the meantime, the first thing you do is treat Covid the same way you treat a foreign military or terrorist cell that murdered 1,000+ civilians a day. By doing so the economy will take care of itself and every lie that Trump told about the Democrats will be countered.
Then, with the trust of the public firmly in tact you pass legislation which shores up all of the unwritten rules Trump broke. By then you've figured out who gets packed into the court and the way you add them. the general public will be a lot more willing to accept this once they see that the government actually works.
Once this change is made you past legislation to ensure voting rights for all citizens and go hard on the environment.
The thing is that if Democrats control the executive branch in both houses they have got to knock this shit out of the park. They have to do a job that is so unquestionably spectacular that issues like wearing a mask, protecting the earth, Universal health care, etc are no longer partisan issues.