I think it is important to realize that the church wasn’t a neat and tidy thing in the beginning.
The great strength of the Apostles was that they had a first-hand knowledge of Our Savior, having walked with Him and studied under Him. Their own reputation as followers of the Messiah was probably what kept a lot of new people seeking after them, and this would have been the beginning of the church infrastructure.
But we have to accept the fact that there were backsliders and people falling away even while Jesus was with us, and that probably continued to happen all through the Apostolic Age. That could easily be the reason the church had to battle gnosticism, some people learned some things as inquirers but just couldn’t buy into what the Apostles were teaching 100%, and so they left to develop their own ideas and peddled them like Sophists and Philosophers would.
Since a lot of the doctrines we take for granted were not clearly spelled out, or clearly thought out, it is easy to see how differences of belief could have worked into the church within the first few generations. On a lot of minor points there must have been a wide variety of opinions, but the followers of the way were not as concerned about those things as we might be on this board. It must have been a huge deal just to accept the resurrection! I would love to have a collection of the earliest baptismal formulae of the various local churches, or to be able to read their hymns, that would tell us just about everything we need to know about possible divergences of belief.
Consider Mary, as an example. Originally she wouldn’t have been an issue at all. We wouldn’t have been debating about whether she mediates graces or intercedes for us, we wouldn’t be praying to her for help or intercession. We could just go to Jerusalem or Epheses and ask her (or maybe write a letter)! Our understanding of her importance didn’t really develop until the divinity of Christ was firmly established by a Council, so there wasn’t much to say on the subject.
Much later Origin (a true genius) was a great seminal thinker in Patristic times, he paved the way for all of the later Patristic authors, his own father was a martyr and he made himself a eunoch for Christ. Yet after his death some of his ideas were condemned. He wasn’t completely sure about everything he was writing and was willing to yield in his opinion to higher church authority but there wasn’t any guidance coming from anywhere at that point, he was basically it, so as far as he knew his ideas were orthodox. There must have been an awful lot of Christians in his position, not being taught doctrines that were yet to be defined, they were left to speculate.
So the so-called divisions couldn’t have occured until the doctrines had gelled, and the far-flung bishops could get together and hash it all out. People had to have a childlike Faith in the Risen Lord, they average believer didn’t have a great deal in the way of Canons or Catechisms to know, they probably hadn’t heard all of the New Testament books that were written, depending upon what local church they belonged to. They needed to trust the bishop, and follow his lead.
What they did have was the Eucharist and the other sacraments. All over the world, even far beyond the borders of the Roman Empire Christian communities had the sacraments.
There just wasn’t as much to fight about early on, except for those danged gnostics and their dualistic fantasies.