I really don't understand the argument for Georgia voting to the left of North Carolina. For Biden to win Georgia, he'll have to be benefitting from an Obama-level black turnout and over-performing Obama and Clinton among southern white voters. That's not out of the question, but I don't see a scenario where he does well enough among those demographics to win Georgia while simultaneously losing North Carolina, where there hasn't been nearly the exodus of white voters to the GOP.
More young voters in Atlanta, and Atlanta has more pull than The Research Triangle or Charlotte for NC. Also fewer ancestral D rural areas that aren't already Republican in GA.
Not to mention Hillary literally did better than Obama's '08 performance in Georgia with little investment, meanwhile NC went rightwards despite investment through the roof.