I was hoping to find some big rural shifts, but though they occurred not among the most dramatic. And goodness knows the various GOTV groups worked heroically, but change comes a lot slower to rural areas, which have their own ways, including a strong religious culture, and like them.
This WaPo article describes 2020 voting in GA's 5 major geographic regions. Comparisons show there was some shift in the Black Belt (a mostly rural, agricultural band between the Piedmont and coastal plain) between 2016 and 2020:
Just as we did before the general election, we divided Georgia into six political states. Atlanta and its suburbs are bluer than ever; the Black Belt is strongly Democratic, but with some Republican opportunities. North Georgia, South Georgia and the Piedmont region drive any Republican win,
BLACK BELT 2016 VOTE TOTAL
Donald Trump 194,353
Hillary Clinton 235,000
BLACK BELT 2020 VOTE TOTAL
Donald Trump 218,970
Joe Biden 280,140
Counties included: Baker, Bibb, Burke, Calhoun, Chattahoochee, Clay, Dooly, Dougherty, Early, Glascock, Hancock, Houston, Jefferson, Lee, Macon, Marion, McDuffie, Miller, Mitchell, Muscogee, Peach, Quitman, Randolph, Richmond, Schley, Stewart, Sumter, Talbot, Taliaferro, Taylor, Terrell, Twiggs, Warren, Washington, Webster, Wilkinson
https://www.washingtonpost.com/graphics/2020/politics/georgia-senate-political-geography/