Without anybody's commentary, testimony or list of sources they should not consult, is there any obvious message which you believe an intelligent, literate person would conclude that the Bible teaches if they read it from cover to cover?
Would it make a difference if they (a) read the sixty-six-book Protestant Bible (using the Tanakh as the Old Testament) or if they (b) read the seventy-three-book Catholic Bible (using the Septuagint as the Old Testament)?
I would strongly advise using the King James Version relying on the Lord Jesus Christ for wisdom in understanding His words as I believe the KJV is keeping the actual message and the truths in His words as found at this link below.
Bible Gateway King James Version
John 5:39
Search the scriptures; for in them ye think ye have eternal life: and they are they which testify of me. 40 And ye will not come to me, that ye might have life.
Matthew 11:25 At that time Jesus answered and said, I thank thee, O Father, Lord of heaven and earth, because thou hast hid these things from the wise and prudent, and hast revealed them unto babes. 26 Even so, Father: for so it seemed good in thy sight. 27 All things are delivered unto me of my Father: and no man knoweth the Son, but the Father; neither knoweth any man the Father, save the Son, and he to whomsoever the Son will reveal him. 28 Come unto me, all ye that labour and are heavy laden, and I will give you rest. 29 Take my yoke upon you, and
learn of me; for I am meek and lowly in heart: and ye shall find rest unto your souls. 30 For my yoke is easy, and my burden is light.
What would your impression be of someone who had read the whole thing and thought there was no over-arching message to it?
Matthew 7:7 Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you: 8 For every one that asketh receiveth; and he that seeketh findeth; and to him that knocketh it shall be opened.
God made a promise that those who seek, shall find. If one looks for reasons not to believe in the Bible, they will look for excuses not to believe. If they look for answers as well as for the truth in the Bible, they will find it & Him.
Those not looking when they read the Bible, can very well wind up not finding anything relevant when reading the Bible, because they were not looking for it nor Him.
If a seeker is really set on finding the truth about God, they can pray to God saying, please reveal Yourself to me in the reading of Your words.
God will keep His promise; and so if a reader finds no over arching message to the Bible, he wasn't really looking for that message.
James 1:5 If any of you lack wisdom, let him ask of God, that giveth to all men liberally, and upbraideth not; and it shall be given him. 6 But let him ask in faith, nothing wavering. For he that wavereth is like a wave of the sea driven with the wind and tossed. 7 For let not that man think that he shall receive any thing of the Lord. 8 A double minded man is unstable in all his ways.