After the 2020 Census I take these estimates with a giant grain of salt.
The $1M question is was there a bigger problem with the 2020 census itself or the annual estimates? Did the census undercount the South or do the estimates systematically overcount the South? In other words, would we expect the deviation to be a one-time thing or is this a persistent result of the difference in methodology where something about the literal census process/funding favors the North in perpetuity?
There's a good argument that the marginal dollar spent on census outreach went further in 2020 due to the pandemic conditions, and Northern/Dem states were more likely to fund outreach. However, there's also a good argument that Northern/Dem states accustomed to a larger social services budget will always be willing to spend relatively more on this than Southern/GOP states...
Also its odd that so many Republicans went out of their way to discredit the idea of counting undocumented immigrants, when that would only go to further help in states like Texas and Florida.