Nobody said it would be easy

That's part of the problem. I see plenty of people insisting "It would be easy if you'd just do it my way!" without considering why people aren't naturally Pareto Optimal in their behaviors.

in places that isn’t America it’s pretty normal to have a party with good ideas that can win seats and inform policies

Where? Seriously, what country are you referring to?

That’s, actually, why there is so much anti-democratic sentiment going on, the same plutocrats spend billions on spreading the idea that democracy is pointless and voting doesn’t work so people shouldn’t bother.

The presumption that American liberal governance is a democracy fuels that sentiment. When you interrogate why so many unpopular people end up in high office, you quickly pick up on anti-democratic trends in the electoral system. Candidates like Henry Cuellar, John Whitmire, and Janet Mills hold their offices through a combination of corruption and dirty tricks, poisoning the party brand for more well-meaning campaigners as a result.

One area in which Republicans seem to be ahead of their Democrat peers is in their willingness to toss incumbents out at the primary level. Say what you will about the average GOP voter, but they were willing to toss Eric Cantor out on his ass and snub Jeb Bush from the general election during some hotly contested election cycles. The "Vote Blue No Matter Who" line doesn't seem to work the same on conservative voters. As a result, they have much more agency within their local, state, and national organizations.

You don't need a brand new party to fix the problem of anti-democratic governance. But you do need organizers and activists willing to cut across the DC party line. Maybe we're beginning to see this, what with Mamdani winning in NYC and Platner upsetting the race in Maine. Idk. But the idea that a third option on the ballot makes the first two less entrenched hasn't born out the way I was promised, over 30 years ago, when Libertarians, Reforms, and Greens were selling it.