To understand God is to believe in Him. If you don't believe in Him you can't possibly understand anything about Him and end up comparing Him with everything else you don't believe. It's redundant.
I do think there is a degree of truth in the first assertion, but intellectually, it would be rather easy to point out things which we may claim understanding of, but don't believe in, by choice. Unicorns is one of around umpteen thousand examples I could put forth.
If making idols of God (via a book, a person, so on and so forth), it would be putting an idol (or symbol) before the Spirit/Word, and then claiming the idol is 'truth.' It could, quite easily, get in the way of understanding. It could, quite plausibly, get in the way of acceptance of (literal) truth.
To me, you conveyed a perfect example of this, when you said:
What I think does not matter. The written word of God is what matters.
You see that external thought has nothing whatever to do with truth. Truth is. Jesus is truth. Jesus is the way, the truth and the life.
If you don't believe that or entertain it as probable truth you can't possibly understand the Christian faith. It isn't like a game of monopoly.
Apparently, for many (Christians) the external thought of the passage: "I am the way and the truth and the life. No one comes to the Father except through me" is their truth. But this is not what the passage literally states. Wouldn't an infallible God, looking to convey inerrant understanding of "the way" be clear that this only pertains to Jesus (or messenger) if that were actually the case? IOW, the passage is not written as, "Jesus is the way and the truth and the life. No one comes to the Father except through Jesus." Because this is not what is written, then it is plausible this is not what is intended for understanding. Furthermore, projecting Jesus onto that passage as if only about him is: a) adding to the scripture and b) perhaps idolatry, especially if that is deemed the only way to understand it. It would literally be projecting an external truth onto the message. Not to mention a fundamental message about Christianity, aka The Way.
Me, I read the passage, as it is literally written: I am the way and the truth and the life. No one comes to the Father except through me.
As the message applies to all, then the "me" within it is conveying an understanding of truth that is highly internal, arguably, strictly internal. Intended to be internalized.
But as I fully get there is a whole lot of Christian folk who may (strongly) disagree with such an understanding, it then goes to show that the understanding of God/Divinity has at least 2 ongoing interpretations. One that is intended to be internalized by all, on a path toward the Truth of Self, or Know thy Self. And another interpretation intended to make idols out of the message provided by messengers, as if the external understanding is the righteous, and only possible understanding. Of God.