Cobb and Gwinnett searchers type the suburb, not the metro
People here identify with Marietta or Decatur long before they identify with Atlanta, and their search language shows it.
Pull your own query report for a month and sort by the location words in it. Suburb names show up more often than the metro name does. Each of those is a smaller auction with a shorter list of firms bidding for attention.
A county page can carry real substance. Which court a matter of that type is generally filed in, how local practice tends to run, how long the drive is from that suburb to your office at four in the afternoon. Practice varies from one county to the next, so keep procedural claims general and send readers to the court's own site.
The failure mode is thin pages. Twenty near identical suburb pages with the place name swapped is a doorway pattern, and it has been getting demoted for years. Write six pages you would email to a client, not sixty you would be embarrassed to.
Order them by where you already take matters. You can write honestly about Fulton and DeKalb if that is where you appear every week. You cannot write honestly about a county you have never filed in.