DaasShnayim: I understood the Rambam the sameway you did. He begins by saying that the answer is longer than measurable land and vaster than the sea, so he obviously never intended for the reader to think that he was attempting to answer the question fully. Additionally, he says that the answer hinges on understanding how the Ribono Shel Olam’s daas works, which he then says is incomprehensible to us humans. So he clearly was simply writing enough on the subject to give the reader an idea of what the general concept of the answer is.
The Raavad was arguing with the Rambam’s approach, as he believed that one should not bring up a question unless a complete answer is given (Hence ??? ??? ???????).