If you say the Catholic Church has no authority, why use the 27 books it canonized in the NT?

Prior to Pope Damasus I at the Council of Rome in 382, the contents of the New Testament varied wildly throughout the Christian world. Many books that were once considered scripture, like "The Shepherd" and "The Teaching of the Twelve" are today forgotten, and some books, like 2 Peter, 2 and 3... show more Prior to Pope Damasus I at the Council of Rome in 382, the contents of the New Testament varied wildly throughout the Christian world. Many books that were once considered scripture, like "The Shepherd" and "The Teaching of the Twelve" are today forgotten, and some books, like 2 Peter, 2 and 3 John and Revelation, were not considered by the whole church to be scripture for the longest time. This is easy enough to verify if you take the trouble.

But it was under Pope Damasus that the 27 books we have today became the official list. Did Damasus and the Council of Rome have that authority? If not, why use only those books?
Update: I don't, Mountain Man. You incorrectly assume I am Catholic. I am not a Christian of any kind, I'm just interested in how Christians relate to each other.
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