This isn't the fault of Democrats. This is a direct result of Republicans in office. Blame voters who aren't voting against Republicans, if anything, because aside from Manchin and Sinema, the elected officials are proposing and passing bills that can have real effects. Only to get stopped at a Republican stonewall.
But that's not even the fundamental issue. As long as a majority of the Senate is represented by a minority of the population, and the electoral college awards more votes to states with less people, the rural minority opinion is going to stay on top.
The nature of far right extremism is dogma, which perfectly encapsulates their fervent devotion to voting for their candidates. Elected Democrats can't save a wand and make the rest of the population do the same.