My views on objective morality

[Neo-Scholastic]

That dilemma does not apply to a monotheistic god whose essense is identical to his existence.  Your trump card is the wrong suit.

...in which case reason continues to serve as the sole means for differentiating the good and bad natures of so-called revealed deities. (You have rendered God to be a completely redundant term that is indistinguishable from the highest possible Good).

People use reason to know about moral objects the same way they about any other type of object. This requirement to use reason would also apply to the highest good or The Good. That does not make reason itself the desired good; but rather the means by which people conceive the good.