The only problem that I see with your contention that early Christianity was as socially dynamic as you seem to indicate is that, aside from a couple of vague, short mentions that are highly contested, there is no mention of this phenomenon in the actual 1st century. By anyone.
Only one problem? I am rejoicing
Mythicists and other extreme skeptics have to contest these kinds of evidence. Of course, they are highly contested by them.
Tacitus, Suetonius and Pliny the Younger wrote about Christians very soon after the end of the 1st century.
According to you, Jesus died in the 30's and by the 60's Christianity was a movement so prevalent in the city of Rome that it had the rulers of Rome up in arms. And yet no one mentioned it until 80 years after the death of Jesus.
I already explained to spin that the Christians were selected by Nero as scapegoats because they were hated by the populace.
As far as reporting the rise of Christianity in non-Christian texts written in the 1st century, we have to consider we have relatively few surviving texts written in antiquity, that a huge amount of texts written then have disappeared or got destroyed.
This means that no one wrote anything about Christians or Christianity for 80 years even though it was a quickly spreading and dynamic cult.
But Paul's epistles, Acts, 1 Peter, Revelation (which I take written in the 1st century) certainly testify to a relatively quickly spreading and dynamic cult.
And if I remember well, you were considering Paul's epistles as written in the 1st century BCE, which would make the "problem" even worse.