I am sorry you still are intertwined with the Roman Catholic thinking of Primacy over ALL CHURCHES. As you have stated: "that Rome held a divine primacy over all churches for the first 900 years."
The Bishop of any church only has ecclesial authority over HIS OWN church or jurisdiction not over other churches / jurisdictions.
Nowhere will you find that the Bishop of Rome had legitimate authority over any other jurisdiction other than his own.
Read Canon VI of the Ecumenical Council of Nice you will find that the Metropolitans of Alexandria, Antioch, and Rome had EQUAL authority over their OWN churches.
First Oecumenical Synod of Nicaea c.325 AD
Canon VI
Let the ancient customs in Egypt, Libya and Pentapolis prevail, that the Bishop of Alexandria have jurisdiction in all these, since the like is customary for the Bishop of Rome also. Likewise in Antioch and the other provinces, let the Churches retain their privileges. And this is to be universally understood, that if any one be made bishop without the consent of the Metropolitan, the great Synod has declared that such a man ought not to be a bishop. If, however, two or three bishops shall from natural love of contradiction, oppose the common suffrage of the rest, it being reasonable and in accordance with the ecclesiastical law, then let the choice of the majority prevail.
OK. So here is the understanding that you most desperately need. Rome up until the 9th Century WAS the par excellence of churches. Rome was a relatively safe haven from conspiracies, intrigues, and heresies that cropped up in the more affluent Eastern Empire. However, during the late 8th century the Bishops of Rome made a bargain with the devil and who they are inslaved TO THIS DAY!
I don't know the definitive cut-off date (756AD -1054AD) from the Lord Jesus Christ and His Church but know this:
Every Roman Catholic baptism, every ordination, and every eucharistic celebration has NO salvific value whatsoever. What is truly remarkable is that the people who most condemn Rome as “graceless” are no lesser than the recognized SAINTS of the Orthodox Church.
Take Saint Photios the Great, Saint Mark of Ephesus, or more recently Saint Nektarios of Pentapolis, and Saint Justin Popovic. Every one of them has condemned Papism in word and deed.
Yet, Incognito you find that Rome, the Pope has some kind of redeeming value as the head of a wealthy and powerful institution. Indeed he is but that institution has NOTHING to do with the Church of Jesus Christ. In fact he and his organization is a sworn enemy of all true Christians.
This Pope and any other future Pope is the forerunner to Antichrist and Orthodox Christians should have nothing to do with him. That is how holy Saints see the Pope it is time you do the same.
P.S. Try not to focus so much on the imperfections that Orthodoxia has but instead look to your own sinful nature as I look to mine. God in His own way will take care of us if we put our trust in Him.
Peace.