“The drop is especially steep in the swing states of Georgia and North Carolina, with declines of 84% and 75% respectively.”
In Georgia, new laws in 2021 made it much more difficult to request a mail-in ballot. 2022 was an off-year election, but mail-in ballots in the November General Election were down about 80% over 2020, a big decline. Dems in GA have been forced to go back to relying on turn-out for in-person voting, ballot harvesting and middle of the night dumps into drop boxes are not working in GA.
When the drop boxes are mandated to be in government buildings and other restricted access and heavily monitored places, you tend not to get so many mules willing to stuff those drop boxes in the middle of the night.