Whether Paul laid feather to scroll, or one of his students did, is irrelevant. What is relevant is that at the time the Apostles were alive Hebrews was a normative Pauline account, and that the Church treats it as such.

The only reason any of the Scriptures are worth discussing at all is that they were incorporated into the canon by the Church. If you don’t care for its authority, just take a pen and scratch all the Scriptures you don’t like. That's what your New Testament scholars do.

My argument would begin “Christ founded a Church, the Catholic Church is the one He founded, He commanded it to teach with authority, and gave it authority and the indwelling of the Holy Spirit to teach truth.”

Your argument, then, begins “He did not!”

Let's just say I'm underwhelmed.

You and I are not the same thing, nor do we adhere to the same Church.