Really? I thought the Orthodox accepted the Council of Ephesus (and Chaldeon) which taught the doctrine of the hypostatic union. Surely you are not saying that the Orthodox don’t accept the hypostatic union.
Also, don’t the Orthodox accept that Mary is Theotokos (taught by the Council of Ephesus, as a response to the idea of Christotokos)? That’s a Greek word - I kinda thought the Orthodox would be on-board with this particular development.
Don’t the Orthodox also accept the development of our understanding if Christology which led the Nicene Council Fathers (who were all Greek - it was a Greek Council in a Greek city) to select the (Greek) word Homoousian (instead of homounion) in the Creed? A subtle, but significant, difference.
Doctrine always develops, and it will never stop developing. It is developing in our own lifetimes (for example, the softening of the position on salvation of unbaptized infants who die - we now have “hope” instead of, well, something else).
I see the Orthodox Church as much like the Jewish Church (or the Anglican Church). Correct me if I’m wrong, but there is no real authority - the Patriarch of Constantinople is like the Anglican Archbishop of Canterbury - a “first among equals,” having no intrinsic authority from his Office. The Greek Christians once held Ecumenical Councils (everybody at Nicea was Greek). Can the Orthodox call an Ecumenical Council today? I don’t think so. And, worse, they think that’s OK. In this way, they are like the Jewish Church - with no central authority structure and no way to promulgate (not change) doctrine relevant to the times. No way to authoritatively interpret an ancient doctrine (so, in this way, they are like protestants, where everyone is free to interpret Scriptures as they please).