DSA for example. They are increasing their influence, for example they have several elected members on the LA Board of Supervisors, not to mention the mayor of the most important US city. They are absolutely dedicated to wrecking the place and they are doing a great job of it in LA at least. That's the direction I see the Democrats going, somewhat in response to Trump, which is bad all around.
It’s the same on the right. If all you have to offer is the same corrupt schmucks, people will vote for the more extreme option out of spite
Besides Biden and Harris having some of the worst draw in any presidential election, check out the candidates for California's gubernatorial election. They're tripping over each other, trying to show that they can all be more scandalous than the current governor.