Republicans accept a post-truth society where everything is someone's propaganda, that the federal government is out to get them and that the union would be better served as a union of state-level republics. Democrats still believe in the existence of a ground truth and want a union with centralized control (i.e., they are Federalists). Like the Federalists, the Democrats are backed by wealthy financial states (New York, California) as opposed to more rural/working-class states (Alabama, Ohio) and support heavy industrial subsidies (Biden's IRA, CHIPS) as well as weak state governments.

This is a fundamental difference that explains a lot, actually. The role of government has always been to convince populations to pursue the policy goals of the elite. The foundations of representative democracy involve choosing which elites' policy goals to follow. The Republicans want to follow state elites (to borrow a Chinese proverb, the mountains are high and the President is far away). The Democrats want to follow federal elites.

Here's the real problem. The US gets to choose between a career politician and a career businessman (swindler, by definition). Who represents the working class? Who represents the people who actually built America's economy?