Georgia returned around 1,430,000 African-American votes in 2020. 88% win for Biden = 1,260,000 votes. Current early voting for A-A has broken 1 million so 400,000 left to equal the 2020 total. I think they'll sail past that.
Total vote was 4,936,000 and already over 4 million have voted. The problem for Harris is that the rural whites are out in vast numbers.
The other problem is that she is unlikely to hit 88% as she is no Joe Biden. Very tight in Georgia.