Suppose you have never heard music, and you are watching a video of a superb ballet, with the sound turned off. And then someone turns the sound on. You now know a dimension of the dance you wouldn’t have expected or thought of. It transforms your understanding of the ballet radically.
Similarly, but more radically, when we humans learned that the perfectly one God is three persons, we learned something that we would not have expected, something that not only we wouldn’t have thought of, but something that we would have likely denied is at all possible. It is something that should radically (in both the etymological and the common senses of the word) transform all of our understanding of God. Of course, what we learned turns out to be logically compatible with the doctrine of God’s unity, but that it was compatible is a part of the surprise.
I suspect that similar transformations of our understanding of God await in heaven. Doctrines that are related to our doctrinal understanding of God as the doctrine of the Trinity is to the unity and simplicity of God. Experience that are radically different in kind from anything we have had.
But is it not plausible that God is such that any finite understanding of him is subject to such transformation? If so, then this gives us one way of countering the “eternal ennui” worry about heaven. For such transformations of our understanding of, and hence of our loving relationship with, God could occur for eternity then.