Your thought process here is irrational; Mormons added the Book of Mormon to the Canon to make their own, check; Muslims are not Christians and did not add to scripture, they created their own book; fail, Catholics defined and preserved the Canon that you rely on; both Catholics and Protestants value the Early Fathers for context and history, neither include them in the Canon, which is why I ask where you learned this ? It sounds like a separatist sect or cult to me.
If you want to think adding to scripture is what you want to base your religion on have at it. But when you come in here promoting your religions additions to scripture claiming to be the “one true church” don’t expect consensus any more than Muslims or Mormons should. If you add to what the apostles taught then I and those who hold to scripture will consider what you teach as “accursed” just as the Holy Spirit through Paul tells us to do. I am sure that is “irrational” to you just as it is to Mormons and Muslims or any other religious person who doesn’t hold scripture to be supreme.