We don't need a new party to begin with. Just start by going independent.
It's the same thing that we needed to be employed this election cycle, but at a larger scale. The Blue MAGA/ Any blue will do/ "Trump bad, you have to vote Blue" is the precise reason we lost this election, because the gave the did not ask anything of the candidate, which gave the candidate cover to not have to shift to more generally popular positions that would get them elected. Blue MAGA threw the opportunity, when Kamala was on a trajectory to be in the mid to high 50's in October, by effectively making the argument that we can't demand anything if this candidate because Trump is too great a threat. But the reality of that is that the demands laid down on a candidate serve the important function that they drag a candidate into more generally popular positions.
Kamala had no real economic plan, and when she said "I would do nothing differently", she's telling Americans, 60% of whom are living paycheck to paycheck, that this is what her policy is going to be.
So if we're going to blame voters for a failure this election cycle, we need to be clear that the voters to blame are the ones who accepted less and little, and who abused and defeated those who wanted the candidate to move on specific policy positions. It was rampant and structural on Lemmy, and I've heard that it was similarly bad on Reddit. Extremely biased moderation here turned communities like c/News, c/Political_Memes, and c/politics into echo chambers where any pushback against an obviously failing and now obviously failed political rhetoric was basically site sponsored. And that needs to be called out and addressed. It literally cost the Democrats this election, and some of the most prominent names in Lemmy were responsible for it. Now obviously Lemmy is tiny and the impact was microscopic, but the same pattern was repeated for much larger platforms like reddit.
It started a couple months before with a tiktok video that got basically repeated regarding "strategic voting". The problem, however, is that the strategy outlined is completely half baked. It doesn't actually work because it keeps candidates unaccountable for having to "go to where their voters are" and get their votes. The result is that the candidate is afforded the opportunity to maintain policy positions that are broadly unpopular because they don't think they need to move to get voters. It's not good strategy, and both 2016, and 2024 offer direct evidence for this, while 2020 offers the counterfactual (Biden did shift in policy, effectively handing over the platform to Bernie, and he gathered the necessary coalition of voters to win as a result).
Going independent is what Democratic voters needed to do in this election to force Kamala into more popular positions. She didn't feel the pressure to do so and lost in a frankly, almost unmitigated disaster of a campaign. And she was afforded the opportunity to do so by voters who demanded nothing for their votes. Going independent takes those votes of the table and makes it beyond clear that they are simply not yours to begin with.