Conflicting statements in the bible

[Neo-Scholastic]

All the "answers" to this dilemma are built upon submitting that one cannot understand god's reason for authoring morality,...one major problem with this approach, which Aquinas missed...If humans are unable to understand the basis of morality of that god authors, then they're equally unable to understand the moral itself and thus it falls back to an arbitrary command.

Your interpretation of Aquinas seems colored by your desire to see his argument fail. The dilemma depends on our conception of what is good, making it a problem of epistomology.

Our conceptions of what is good come from judgments we make about the various states of affairs. We compare these with each other, find common features, and conceive a universal category of goodness. Since those common features accord with attributes of God, God serves a universal standard.

Thus the dilemma is not a dilemma about God. The dilemma is about how we identify what is good. It is not like an ideal good exists apart from God, it is whether God's nature matches our human abstract conception of good for which God can be a common standard. Or to put it another way. Since our conception of an ideal good is identical to the nature of God, we feel justified in saying that God's nature is the ideal good.

I think it is important to add the following. One thing that makes Christianity unique is that God is not just a collection of abstract principles. He is a real Person that exemplifies the highest standard we can conceive. Thus serving Him is following a just and merciful king, not just adhering to a particular philosophy.

Thus you either accept God as the standard or you do not. "Choose this day whom ye shall serve." Should you obey God? Its up to you. Choose wisely.