Iambiguous neglected to include 'omnibenevolent' as a required attribute of this god. Including it would result in an optimal objective morality for humans.Just a thought. Omniscience and omnipotence have no moral significance or entailment. It doesn't follow that an all-knowing and all-powerful being will or must be all-good. It could just as well be all-bad.
I will give him the benefit of the doubt and assume that he did that intentionally.
In which case, the god acts as a governing body which establishes a set of rules and penalties for breaking the rules. Something like an standards organization setting the official rules of basketball or chess or mechanical fasteners, etc.
Words like "all-good" and "all-bad" seem like objective terms.
The god would have knowledge of consequences and the best goals to pursue. That would be moral knowledge.The claim that an all-knowing being would have all-knowledge of morality assumes there is such a thing as moral knowledge - which begs the question.
Even subjective morality must be based on some sort of knowledge. How else would a subjectivist choose an action?