I'm sorry, men quite obviously wrote the Bible, unless you believe it sprang from a tree or rock printed and bound, or some other miraculous method of appearance.
Believing that does not discredit it. Men have written fine, even divinely inspired works. The Declaration and the Constitution, or the Statute of Religious Freedom, or even The Screwtape Letters.
I would believe it, even written by men, if it accords with what I believe is right and wrong, and what can be learned through prayer and reflection.
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.