As narrow as God.
It has to be. If we could manufacture our own good, rather than be constrained to share in the good that God is, we wouldn’t need God.
Our good is derivative — just like the moonlight came from the sun.
And guess what. Read the story about what went on in the Garden of Eden. That very lie that we wouldn’t need God was sold to a willing, gullible humanity through Adam and Eve.
I don’t disagree with anything you’ve said using “good” in reference to the Deity. However, the word as it is most commonly used has nothing whatever to do with the nature of the Deity, as may be confirmed by any standard dictionary.