You argued yourself into a corner and then refused to acknowledge it. You said the Church had no authority to add anything to Scripture, when "Scripture" at the time meant the Old Testament.
SD
The canon of Scripture is what God intended it to be not what the Church intended it to be. The Church as the Bride of Christ is guided and protected through the Holy Spirit and the God-breathed Word of God, the Holy Scriptures, both Old and New Testament. If you think that the early church fathers decided without the authority of God which were canoncial books and which were not you are mistaken. When Christ spoke of the Scriptures he spoke of the totality of the Scriptures with the full knowledge of what was canonical before even the beginning of time.