I recently listened to a podcast on the doctrine of Divine Simplicity, which I found really helpful; https://www.reformation21.org/mos/podcast/43356 It lays out the case for why this is a key doctrine for Christianity, in lieu of recent attacks on it by wayward evangelicals Karl Trueman and James Dolezal make the startling case that if divine simplicity is lost, then the idea of the Trinity itself will be soon next to follow…
The concept of Divine Simplicity is linked to the aseity of God, which is to say, his status as an eternal and uncreated Being. God is there fore simple in that he transcends any category. He is what his attributes are: he does not manifest omniscience, for example; he is omniscience. The Triune God is without "parts" (a formulation that confuses even many theologians!) -- that is, God is unified in Being, thought, and action. There are conservative theologians who disagree with this idea, though. Alvin Plantinga argues against it (at least in the Thomist sense) -- if God is what his attributes are, then God ceases to be a Person and instead would be a description, a property. It's an abstruse point, and I doubt it would resonate much with anyone besides theologians and philosophers. To me, this is a case of academic philosophical language getting in the way of theological language.