Universal healthcare
What major figure in Democratic party has seriously fought for this?
electoral reform
No Democrat is seriously looking into real electoral reform that doesn't benefit their party. First-past-the-post will never be changed under their leadership. This voting system allows them to shift blame to voters to the left of them (that they alienate) for voting Green/et. al. They engage in more voter suppression activities than they spend time arguing for serious electoral reform.
https://www.carolinajournal.com/nc-democrats-forced-to-pay-green-party-for-frivolous-intervention
https://arizonaglobe.com/legal/democrats-sue-to-block-green-candidate/
https://thenevadaindependent.com/article/nevada-democrats-sue-to-block-green-party-from-2024-ballot
It goes on and on and on and on if you look at lawsuits and complaints against other parties or look further into the past.
If Democrats had even 1% of the fight that they have against third parties and put that towards positive change and actual solutions, they would've been able to accomplish some of the things you listed.
When the shelves are empty because everything comes from China or relies on imports from China, when there is a food crisis and people are sent to the fields because Trump deported a significant chunk of our agricultural labor force (40% of US agricultural workers are undocumented immigrants), when people become unable to afford groceries and other essentials, and so forth - that is the moment that change will happen.
Trump et. al have already done so many things that are blatantly against the law. Contempt of court and not respecting his oath to uphold the constitution being the least of them. Where are the Democrats when you need them? Writing strongly-worded letters to Trump?
The obvious solution is to stop playing games, stop waiting for the Democrats to save us, and seize the moment. That includes creating a real American democracy.