As your following explanation makes clear, it's actually an unrepresentative democracy.
For further reading, I recommend learning about the Citizens United vs FEC case that vastly increased the amount of money going to politicians, far over individual donation limits.
Even if we magically fixed the electoral system tomorrow, the results would be superficial. Sure, we might see more Democrats in office—but if they’re still beholden to massive, uncapped donations, how can we expect them to enact real, meaningful change?
This problem with money in politics is not something that only affects one party. It's a systematic issue that needs regulation. Without real regulation on money in politics, everything else is a band-aid on an open and festering wound.
Both of which are infinitely better than what we have now, which is bastardized worst elements of both.
But because both sides will never agree we'll get neither, only the current hellscape.
You can probably see where the problem comes in. Take, for example, a politician who campaigns on Medicare for All or universal healthcare. To win an election, they often need massive campaign funding—much of which comes from wealthy donors, including those in the medical or pharmaceutical industries. And once in office, they’re targeted by powerful lobbying efforts worth billions of dollars from those same industries.
In the end, the issue is that politicians can legally receive millions in donations and support from industries whose interests might directly conflict with the needs of the people they’re supposed to represent.
Ultimately though, it is known by most people irrespective of party affiliation that medical costs are out of control. One recent example of this collective understanding was when the united healthcare exec was killed. Before there was even a suspect, people generally knew why he was assassinated. Most people in the U.S. have either been directly affected by the insanity that is our healthcare system, or one of their loved ones has. Those that haven’t yet, it’s just a matter of time. It’s just so pervasive.