The problem is the Democrats aren't far left, they aren't even really left. There is no viable political counterbalance to the right wing in US politics anymore, the so-called left is moving right, and the right is moving further right. Kamala Harris' whole campaign (such as it was) was an attempt to court "moderate" Republicans rather than the base who was never enamored with Biden to begin with.

I agree that first past the post is a problem and this election was more lost by the Democrats than won by the Republicans, but I think it's a myth that any of it has to do with the Democrats going "too far left." Call me when any Democratic Presidential candidate openly calls for dismantling American imperialism and scaling back the military, or criticizes capitalism and endorses nationalized healthcare, education and UBI, or doesn't kiss the ass of police or curry favor with Evangelical Christians, or has immigration policies that actually materially differ from those of Republicans.