You are talking to one of those morally and policy opposed to Trump and also policy opposed to Biden people. I didn't vote for either of them. I cast a protest vote and voted down ballot as I saw fit. Then again, I live in a state where my vote doesn't matter, if we had a popular vote I'd have voted differently just to do my part to get rid of Trump, as I dislike him a helluva lot more than Biden, but in our current system I could vote my conscience guilt free.
Problem is you are confusing American neoliberalism as left. It's not in the least bit. In any other country it'd be a center right party. The nature of discourse and a two party system make it a left party in America, because it's left of the other party, but it's still pretty right on the entire spectrum of policy points. Since you mention gun control specifically, there's absolutely nothing in left politics thats anti gun. Hell Marx was pro arming the proletariat (not an endorsement of Marxism, just making a point here). Sure there's some left identity stuff, but overwhelmingly the Democratic party is center right economically and social policy wise.
I agree that middle ground area is garbage and I don't like it either as it's all feel good half measures while still trying to placate the wealthy and elites while doing nothing tangible for working people, which is why the dems time and again can't win middle America.