Is there anything we can say about the Holy One, blessed be He—what He wants, and so on? Or can we not grasp the concept of divinity at all, such that there’s nothing we can say about Him?

Of course we can. That He exists, that He conducts the world through His thirteen attributes, and that His will is for us to keep the commandments and follow the ways of morality. All this is as obvious as anything, and I don’t see what there is to write about it.