I''m sure you're right as you know a lot more about this than I do. I do remember reading that early Christianity itself (when it was techically just a branch of Judaism) was strongly revised by Saul/Paul, while the rest of the apostles were totally against what he came up with, so it just depends which apostle you want to go by, I guess
.
Yes, Paul of Tarsus, as far as most any scholar is concerned, brought into being the *religion* of Christianity, and when it came time to select writings for the Christian canon, well, most of it wound up being written by Paul, and it was he who spread the new faith in the near east cities of the Roman Empire, and even unto Rome.
The apostles, well, Peter, James, and their gang, were of course suspicious and jealous of Paul's success and they clearly didn't consider him a true "apostle."
Anyway, I do agree that as far as Christianity goes, the Orthodox (some would say the Armenian Orthodox, particularly) has stayed truest to the "official," earliest organized faith.
Personally, I prefer the books that were left out of the canon, as I suspect they come closer to the truth of many matters, and Constantine, after all, was really only interested in the propaganda uses of the curious new faith that had attracted so many.