I was surprised at how close some of the senate races were. Republicans almost won a few races i thought they'd definitely lose.
I am not sure this blue wave of the next 20 years is coming that you are predicting. And if the republicans get their heads out of their ass, i think they can steal back some voters who don't agree with the vocal far left.
Last 4 years the vocal far right chased away voters. Next 4 years the vocal far left may chase some of them back.