Men “penned” the Bible, there’s a difference. If it was their thoughts, it’d have no authority. As for what you find believable, that makes you your own god. The constitution or screwtape letters is only divine where their principles match those in God’s Word.
I am a long ways from being my own God. I can't even lay claim to being the best human, indeed, I'm far from it.
But when I read things in the Bible like Paul's admonition that it's better not to marry, I strongly question whether that's God's word. In fact, I'm pretty sure it's not. I think that's Paul's word, not God's Word.