You got most of your facts straight....except your assertion that Catholics aren't Christians (if I'm reading right, or you're disagreeing that Catholics are OG **my words**) the word 'catholic' simply means universal. The conversion of Constantine changed "Christianity" from a backwater breakaway Jewish sect to what it is now. It's entirely realistic that had that never happened I would probably have been raised either under some traditional Roman belief system or Islamic, cause I hope we can agree that Judaic proselytizing just isn't on the same level as that of Christianity or Islam. The word "catholic" simply means universal.