who would determine that? -
surely you are aware of the church councils throughout history that fixed certain beliefs -
I certainly don't see your version of church government as described in the bible
Which parts don't seem accurate?
Do you find the Bible to differentiate between elders, bishops, and pastors?
Do you see it ranking them in a hierarchy?
What do you make of Jesus telling us not to call people father, teacher, or master, and that leaders in the Church should be an example to the flock, not exercise dominion or authority over them?
Can you help me with scripture that says the keys given to Peter were to be handed down in succession from one person the next?
As to your question, "Who would determine that?", the answer is the Church. Even in the first century there were false teachers who gathered flocks about them. The elders were to guard against such and make sure they were not allowed in the fellowship of believers. To the world outside the Church, this would, of course, make it seem like there are many Christian churches. But the Shepherd knows His flock, and they know Him. It's up to believers to discern by the Spirit which fellowship is truly in Christ, and up to the Spirit to mark them with grace and power. Wisdom, is justified by her children, and the tares are allowed to grow alongside the wheat until the harvest time.
I am aware that church councils have fixed certain beliefs. I am not a scholar of church history, but it is my impression that councils often "fixed" or ratified certain beliefs that were already largely consensual in the body of Christ, sometimes in response to a heresy that was working through parts of the church.