And in my opinion, whether you’re “responsible for your actions” isn’t a question about the nature of reality (ontological), rather a question (or one of several) about how we should act in it (moral).
That’s not my definition it’s almost verbatim from the Oxford English Dictionary. Still, it’s exactly how I feel.
But morality is important to this discussion I think but I cannot put my finger on “why” it is.
What I want to focus on is what leads you to conclude that your will, or your discretion, is not deterministic. Forgetting, if we may, arguments for or against determinism from a physics perspective: what’s the argument from your personal experience? As for morality, I would make the case that ontology should inform morality but not the other way around.