Dear SS ( sincere seeker ):
You are trying to prove that Jesus' status as God/man had been debated for hundred years before finally being settled down that He is indeed a God/man with dual natures.
You seemed to conclude because of those centennial long debates, Jesus being God is just man-made. You do have a good point, and I guess we do need to be concerned if Jesus was man-made or man promoted God.
I did give it a deep thought and I do have more insights than before, thanks for raising this Q.
Let me share with you what my current insight is.
Let's go back to the time when Jesus was walking on this earth as a human being.
His disciples and other believers followed Him for 3 yrs, the most. They saw Him performed many miracles, but basically, most of them thought He was only a human being endowed of special abilities like many prophets before Him. Once in a while, someone like Peter did get revelation from Heaven and realized that Jesus is Christ and the promised Messiah.
But not until Jesus' resurrection and reappearances to them for 40 days and Jesus' ascension to Heaven, that they started to realize that Jesus is also God. For this realization, they became bold to spread the Gospel at the risk of losing their own lives; they are reliable witnesses. As this generation who eye witnessed Jesus' miracles and resurrection passed away, since people were further away from the time when Jesus walked on earth, many of them started to regard Jesus as only God; some of them eliminated Him being a human being out of total respect and admiration. That caused Jesus to be regarded as God only without being God the incarnate since they now had relationship with God the Son but no longer had the human Jesus walking alongside with them on earth.
Therefore, a debate becomes necessarily to decide whether Jesus did have a human nature, whether He is God incarnate. So you see it is His human nature in dispute, not the God nature. Namely, Jesus being God has been proved by His after resurrection appearances and the blood of martyrs but His human nature has been neglected by early pious Christians. So the debates were to confirm that Jesus as God had truly come to this earth to take on human body and human nature. It was not the God nature of Jesus being in dispute. If His God nature were the issue, then your concern to raise the Q would be really having a strong reason.
Trust me , it is not His God nature being in dispute but the dual natures of God/man are in dispute because of our own limits in 3 dimensions, we are not able to comprehend how Jesus could be simultaneously being God and being man. It took 100 yrs for believers to come to the conclusion that Jesus is really God/man.
I hope this clear up the issue you raised.. Indeed, Jesus' human nature not His God nature was in dispute in church history