Would you be able to help out us Romans and elaborate a bit as to what are the theological teachings of the universal Catholic Church which are not contained in the Roman Church teachings. I am familiar with the fasting differences, and receiving Communion in both kinds by a spoon, confession at the altar in front of the priest, no musical instrumentation in Church services, the use and importance of icons, and other disciplinary differences, so there is no need to mention those. I am more concerned about the theological teachings of the universal Church which are separate from the Roman Church teachings.
You’ve got it backwards.
There are a great many Roman Teachings which are not Universal:
The Assumption of Mary while alive
The personal stain of original sin.
The fires of Purgatory
The Immaculate Conception of Mary by Elizabeth (Can’t be free of what one isn’t born with)
Amongst a number of others.
The relevant teaching on the Immaculate conception, that Mary was free from all sin, does not, in the Byzantine Teachings, require being free from the effects of Adam’s sin.
On the Assumption: Romans teach she was assumed while alive; the dogma is that she was taken to heaven, body and soul, but not of need before the death of the body. Byzantine Tradition includes her soul in heaven before her body, and her body dead 3 days when it was assumed.
The Personal Stain of Original Sin holds, essentially, that all are born with a mortal sin upon their soul. Eastern theologies generally accept that one needs baptism to become part of the Family of God, and to assuredly open one to the grace needed for Salvation, but not that we have that stain of Adam’s sin. Adam’s sin cast humanity out of the Garden; all outside it suffer death. Even Mary experienced the death of the Body. We are not born filled with sin through Adam and Eve’s sin, we are instead deprived of divine grace, which, had they not sinned, would have been our Birthright, and through baptism, is restored to us.
Byzantine Theosis does not include purgatorial fire. It does include continuing change, continued prayer, continued growing closer to Christ, and continued benefit from the prayers of the faithful and the saints. But it meets the actual dogmatic definition… which merely includes posthumous purification and satisfaction for sins.
Each of the 23 Churches has its own body of teaching; most of them of any given Rite will be very close to others of that same rite.
the majority of differences are far more subtle.