Teorically the first gondorian bastion is Minas Tirith,the fortress is intended to be a "copy" of minas tirith in-game.
Gondorians may have rebuilt some numenor cities,but we can't compare them.Sauron's leader never ordered to built fortified camps,then should mordor have no fortress?This mskes no sense.Bfme shows ALL the forces a faction have,meaning that even though the white tower is in minas tirith you can build towr guards
In-game you can't build minas tirith,so you think that gondor shouldn't use numenor walls as they shouldn't be able to build them,according to the lore?It's like saying that Ereinion's summon should be deleted because Ereinion is dead.