Tremendous commentary. I think of the Aeneid as more of a transition point in Roman and Greek thought about the future/history from that of fate to one of destiny. A person is resigned to fate. Conversely, to fulfill one's destiny--it must be carried out. I think that this change in attitude prepared the Roman people for Christ and His destiny narrative.
Aeneas has not to submit to that (1:57). Vergil shows the reader what the individual sacrifices when the State (or dynasty) is the goal: war, unhappiness, misery, suffering, the killing of your self. The pious Aeneas of Book I has nothing in common with the killer Aeneas of Book XII. An Epicurean warning against Stoicism: Do not let the Absolute swallow your character, your happiness, your soul.