You say this mockingly, but the fact that Democrats lost an open seat gubernatorial race in a great national environment in the election election cycle immediately preceding 2020 is a very strong piece of evidence that GA isn't quite a top-tier swing state yet.
The national environment/popular vote should always be taken into consideration, yes, but is this the kind of state which swings wildly depending on changes in the national environment/overall popular vote?
Republican percentages in high-profile races since 2012:
2012 (very good year for Democrats): 53.3%
2014 (extremely good year for Republicans): 52.7%/52.8%
2016 (very good year for Republicans): 50.4%
2018 (Democratic wave): 50.2%
Notice the downward trend. There’s also the fact that an outspokenly liberal black woman only lost the state by a point while receiving 48.8% of the vote, which would have been unthinkable in the Democratic wave of 2006. Any way you look at it, this state is a ticking time bomb for Republicans, and it’ll go off sooner rather than later.