If you wanna follow Jesus (according to the best of our information about him), you can't be a Trinitarian quasi polytheist who thinks faith, salvation and works are all disjointed and independent. But Paulian doctrines are nothing but that, and the way for a Roman Empire to convert Jesus' message of accountability and righteousness and his Abrahamic monotheism to something more palatable and in-line with their existing beliefs. This includes but is not limited to: a pantheon of three (with a "human God" as one of those three), "consumption of blood and flesh" rituals, the Day of Judgment no longer being one of actual judgment because if you "believe" "Jesus is God" you're automatically saved, whatever Paulian "grace" was...

The Roman Empire is the grandaddy of all Western imperialistic doctrines and my informed guess is that Paul, who didn't actually know Jesus and even in the Bible he gets told off by Jesus' actual followers, was nothing more than an agent of destabilisation and an infiltrator, perhaps sent by the Romans themselves but if not at least used by them to create what we know now as "Roman Catholicism", which is nothing but a deformed, unrecognisable husk of the teachings of big J. Whether this happened this way or more organically is up to debate, whether Jesus' teachings and Christendom are fundamentally different is not, though, that just requires some basic reading comprehension skills.