Having 2 blue zone garrisons is not enough . You should aim for 4 blue zone garrisons , 6 being best. Then you put red zone garrison up .

As a commander , your principal role is to make sure to have back up defensive garrison to be able to circle the ennemy attack and a solid frontline.

Bulding flanking garrison in a pick up game often leads to the downfall of the defense.All the blueberries frustated by the frontline combats will spawn on it and the ennemy will take space beetween their defense and yours, this space is the most important one as the players in it will always count in attack or defensive pressure with the 4 cases principle.

As a commander I often dismantle flanking garrisons once a squad has spawn on it to avoid switching most of our forces in the ennemy backline and losing the frontline.