What I was getting at is more subtle, We have a phrase in Latin, lex orandi, lex credendi, the law of prayer is the law of belief, the interrelationship between how we pray and what we believe. What I’m interested in would be, for example, if the traditions of an Eastern Catholic have aspects more in common with Orthodoxy than with Roman Catholicism, I would think there would be nuances of differences in expressions of belief of an Eastern Catholic, as compared to a Roman Catholic.
Functionally, most of the byzantine rite churches (14 last I bothered to count) are essentially and liturgically “Orthodox in Union with Rome” and do in fact share most of the doctrinal differences that the Orthodox have, tho not the dogmatic differences. Mary was taken to heaven in parts - soul first, body days later, then reunited. Theosis rather than explicit Purgation.
But one must also understand the core meanings of the terms for that to make sense:
Dogma - what must be believed.
Doctrine - what must be taught, and must act as if believed, but isn’t required to actually be believed.
Rubrics - that which must be done.
In keeping the Orthodox Liturgy, one keeps the Orthodox doctrine, unless one mangles the propers. I’ve seen claims aplenty that the propers have been mangled within the Ruthenian church, but see no actual evidence of that.
The Rubrics vary widely within the EO churches, and even more so amonst the EC churches.
We are prone to many EO books in our bookstores for developing our faith, for they are closer to our understanding than the Roman ones.
Are we the same faith? Depends how you define faith -
If you define “the same faith” by sharing
all doctrines and dogmas, no, and the EO also are not obviously one faith; if it’s just dogmas, yes, the EC’s and Romans are one faith. If it’s “all the dogmas and most of the docrines” then yes - and the EO on the ground are likewise all one faith. If it’s the sharing of the same creed, then, again, yes, but then so are the Orthodox, Lutherans, and non-progressive anglicans.
(The Roman Credo is not the Nicene-Constantinopolitan creed - but rome does accept the NCC as well, and the NCC is the Byzantine standard.)