Bid Orleans, Jefferson and St. Tammany as three separate buys
One geographic target stretched across the whole metro averages three different markets into a number you cannot act on.
Orleans, Jefferson and St. Tammany have separate governments, separate character and, for your purposes, separate buyers. Target them as one blob and Metairie or Kenner can absorb budget you meant to spend elsewhere, invisible in a metro-level report.
Split them out. Same ads and same keyword set if you like, but separate geographic targets, or at minimum separate reporting, so bids can move independently.
Distance behaves differently for federal work. A client on the Northshore does not need to sit in your lobby to hire you, so a click from Mandeville is not worth less by default. The right question is whether Mandeville clicks book and show up.
Target location of presence, not location of interest. Someone in another state researching New Orleans firms is a different buy, usually a worse one, and belongs in its own campaign if you want it at all.