There is not a dedicated group of FAs that are assigned to flagship cabins.
FAs bid for the routes and cabin they want to work on.
The prioritization of who is at the top and gets what they want is not based on training, is not based on performance.
Seniority trumps everything else.
You can train the FAs as much as you want, but that' not going to change how the FAs perform as there is no accountability.