I think it's important to let the Bible speak for itself
This is impossible of course. Unless you think it speaks differently to different people. Which would make the statement meaningless.
No, not "impossible, of course." "For the word of God is living...it penetrades even to dividing soul and spirit, joints and marrow; it judges the thoughts and attitudes of the heart." (Heb. 4:12)
Does it speak differently to different people? Yes. Why? Something "objectively" flawed with the Bible?
No. But even if I go to another land today, and every word I speak is translated well by an excellent translator, what I say has the potential of being interpreted in different ways. Why? For one, I may use a phrase relevant to American culture, but it's a totally unknown concept to most of my hearers. There was nothing wrong w/what I said; there was not wrong w/the translation; but folks not understanding the culture I come from will miss out on some things.
When we're talking about Scripture and spiritual concepts, there's also another concept that has nothing to do with the plain meaning or objective presentation of Scripture. It's the concept of spiritual illumination.
1 Cor. 2:10-16: v. 10: "God has revealed by his Spirit..." v. 12: a Spirit of understanding. v. 13: "words taught by the Spirit, expressing spiritual truths in spiritual words." v. 14: "The man without the Spirit does not accept the things that come from the Spirit of God, for they are foolishness to him, and he CANNOT understand them, because they are spiritually discerned."
So, you're right on at least one count: In one sense, the Bible doesn't stand alone. It doesn't only speak for itself. The Holy Spirit helps us interpret and understand it properly.
I'm thinking what you mean by what you wrote is that it takes an authoritative church to properly pronounce what is and isn't true.