In the Middle Ages the point of Christian scholarship was to iron out the contradictions plus work out the problems of theology based on the Neo Platonic school.  One such problem was Divine simplicity. The way this was done by Boethius was mainly to stick to Neo Platonism. This was serious work and was not made irrelevant by subsequent people, nor Martin Luther.  The Jewish world faced a similar problem. To iron out the contradictions and meaning of the OT and in the Talmud. Plus similar problems in Theology. In any case, all this is based on one idea. There is no essential contradiction in the word of God. What Protestants do is to ignore all these problems. If a certain verse appeals to one, then he or she grabs it and that is that. Divine simplicity never bothers Protestant at all. All the problems facing the Middle Ages were simply swept under the carpet, not answered.

As about a thousand years of trouble with Divine simplicity did not get very far, Aquinas simply  went to Aristotle following Maimonides.This was very helpful as far as Divine simplicity was concerned but made other problems. Kelley Ross thinks the problems with Aristotle are so great that the logical thing to do was to go back to Plato. [Not that Aquinas or Maimonides could have done that since they were busy working out their system. But later on people when they saw the problems could have simply gone back to a Neo Platonic approach. But in the West that is not what happened. People went into a far more radical empirical-ism than that contemplated by Aristotle. So the Western Judaic Christian  world tends to be pretty secular.
[Dr. Kelley Ross: However, a stricter empiricism again creates the difficulty that the apparent "form" of an object cannot provide knowledge of an end (an entelechy) that is only implicit in the present object, and so hidden to present knowledge.
Curiously, the reaction to this was not immediately a new Platonism or Neoplatonism, but a more extreme empiricism:  The Nominalists overcame the Aristotelian difficulty by rejecting Realism altogether.]

My own feeling about all this is the to learn the Oral and Written Law and take a Neo Platonic approach. I do not think Aquinas was very successful in answering the Divine simplicity problem. Or rather let me say I think the Rambam did a better job by simply sticking with Aristotle and the First Cause. Though I can appreciate the efforts of Aquinas and what he did for natural law but in terms of the NT I think he was simply trying to do the impossible. As long as Paul is part of the NT there can not be any way to get him to correspond to the OT