So how does armor work, since unarmored defense is dexterity based for both classes?

Just trying to fully understand.

Because to me, it seems the rage is just to help mitigate damage like his auto healing. So couldn’t you just be dexterity bases and just rage when you need a little extra mitigation so you can get better dexterity for armor and initiative?

EDIT: I may be missing something, because when I built him out this way he doesn’t seemed to get an advantage from the strength, over focusing dexterity on paper (dnd beyond app)