Not much. All this really shows is that black Democrats don't show up when the party doesn't try to turn them out (shocker). You saw a similar dynamic in 2022, where black turnout was pretty bad across the South but was decent in Georgia despite being a midterm.
Even in Georgia, Walker outperformed Trump in the black belt despite being a very weak candidate and Warnock being a perfect fit with them, and Kemp/Raffensperger put up numbers way better, with the latter even flipping GA-02.
Which is all to be expected in an area with such high racial polarization in a midterm. Although black turnout was better in Georgia, the nature of midterms is that these areas will swing right.