This is an interesting assertion, and I would like to see you substantiate that. There are certainly a lot of holes in my own knowledge that I would like to repair.
However, the Churches I am referencing --- the ancient "non-Roman", Apostle-founded churches such as the Eastern Orthodox, and the ancient "non-Byzantine" Orthodox churches (some of them termed "Oriental") such as the Copts, the Armenians, the Assyrian Church of the East, etc. --- all still hand on through the generations what was handed on to them from the cradle-years of the Christian Faith: priestly/hierarchical governance; the Liturgy; the veneration and intercession of the Saints and Ever-Virgin Mary; prayers for the souls of the faithful departed; the life of the Sacraments; and the Real Presence (however they express it in their own languages) of the Lord Jesus in the Holy Sacrifice of the Altar.
Grateful for anything you can add here about these other Apostle-founded Churches ---Copts, Armenians, etc. It would be of real interest.
Theotokos of the Sign However, the Churches I am referencing --- the ancient "non-Roman", Apostle-founded churches such as the Eastern Orthodox, and the ancient "non-Byzantine" Orthodox churches (some of them termed "Oriental") such as the Copts, the Armenians, the Assyrian Church of the East, etc. --- all still hand on through the generations what was handed on to them from the cradle-years of the Christian Faith: priestly/hierarchical governance; the Liturgy; the veneration and intercession of the Saints and Ever-Virgin Mary; prayers for the souls of the faithful departed; the life of the Sacraments; and the Real Presence (however they express it in their own languages) of the Lord Jesus in the Holy Sacrifice of the Altar. I'll stick with what we have revealed to us in the NT as it is the only inspired text we agree upon.
The writings of the ECFs the EO and the RCC rely upon are not considered inspired and in several cases contradictory of each other.
From the Jerusalem Council:
19“Therefore it is my judgment that we do not trouble those who are turning to God from among the Gentiles, 20but that we write to them that they abstain from things contaminated by idols and from fornication and from what is strangled and from blood. Acts 15:19-20 NASB
This passage, along with several others, contradicts the RCC claim we have to literally eat and drink His flesh and blood.
Regarding your other comment:
priestly/hierarchical governance; Not substantiated in the NT descriptions of leadership
the veneration and intercession of the Saints and Ever-Virgin Mary; Not substantiated in the NT
prayers for the souls of the faithful departed;Not substantiated in the NT
and the Real Presence (however they express it in their own languages) of the Lord Jesus in the Holy Sacrifice of the Altar. Not substantiated in the NT