Bible Alone can’t prove the canon of the Bible nor can it prove how to determine the canon since God did not reveal by way of written revelation to us. You can read every book of the Bible and you’re not going to find any of them that specify the Bibles own table of contents. In fact, I’m going to add to the list of things that is “extra” or “added” from God’s word. You could read every book of the Bible and your not going to find written in any of the books of the Bible, the doctrine that we should consult the Bible Alone to determine the content of our Christian faith.
So when Christ made previsions to hand on the faith. He never told the Church, as your handing on the faith, be sure to consult this list of books, these 27 canonical books in the NT and define everything against that standard. He never said that. On the contrary, Christ delivered his teaching orally as a tradition and trusted it NOT to a book but to individuals, to living people and commanded them to pass it on and gave them a promise of Divine assistance. (Sacred Tradition, teaching office of the Church, and the sacred liturgy. He said Do this in memory of me, He said to baptize, He said who ever sins you forgive are forgiven.)
If you think about it, if you go read the NT. The NT is not a manual on Christian worship. There is no document in the NT that says when Christians come together this is how you should worship. This is the order of worship. This what the liturgy should look like, this is what the one who presides should do. There’s nothing like that. Rather the NT, presumes the preexist of the sacred liturgy. St Paul writes to members of the Churches like they know what’s going on. Because he knows that they know it by Sacred Tradition.