The metaphysics of A-T is focused on defining an ontology of reality, but it doesn’t do so well at ontogeny. It describes how things are, not as much about how things got the way they are. This may be why origins is harder for A-T.
I have a theory though. Aristotle was an eternalist. Because he didn’t believe the universe had a beginning, he didn’t need to think about ontogeny or origins in the same way as us.
So, when we think about Thomism, to what extent is it unduly influenced by eternalist?