If the job was done "perfectly", surely the message would be clear.
The central message IS clear to all who have truly been born from above and have been indwelt by the Spirit. But I suspect that, like the Roman Catholic church, you misunderstand the purpose of the Scriptures. Their purpose is not in fact so that we can build up a huge doctrinal system, it is so that God can bring home His message personally to those who read them. 2 Tim 3.15-17 explain their purposes. To make us wise unto salvation, and to teach, rebuke and exhort us so that we become righteouscomplete and equipped for every good work.
Obviously it is not clear because sincere, genuine, educated seekers-after
-truth study the very same texts and come up with thousands of different doctrines and beliefs.
You see your problem? You have a totally wrong idea about the Scriptures. You seem to think that they are intended to makes us All have the same doctrines and belief. But that is not what Paul said. There are very few doctrine and beliefs that it is necessary to be 'right' on. These include the triunity of God, the fact that Jesus is both true God and true man, and is retuning to take home His own and judge the world, and that salvation is obtainable through the blood of His cross. Otherwise Scripture deals with individuals according to their need. It brings home to each individual what he at that time needs to have assurance on in his heart. And every individual is different, so each need different applications.
There will be no 'doctrinal test' when we meet God. The only question that will matter is, 'did you truly know the Lord Jesus Christ and trust Him alone for salvation, did you receive the Holy Spirit, did this result in righteousness within you?'
Apart from the above all our differing doctrines and beliefs will be irrelevant.
You only have to examine the very differing views of the early and later fathers to see that this is so. Doctrine was so diverse among them that if 'correct doctrine' had been what was required few would have been saved. Were the Arians who gathered at the Council of Nicea bearing the broken limbs, signs of torture and many scars obtained because of their testimony to Jesus Christ all lost? I don't personally think so. If their HEARTS were true to Jesus Christ as their personal Saviour I do not think that God would overpress niceties of doctrine on a subject not fully understood.