I'm afraid that, rather than projecting your perspective back, you've projected it across. Most modern Western people are formed, to some degree or another, by the influence of Hebraic civilization. All the examples you cited are, like you, pagan. The division here is less about era than worldview.
There is also the matter of "absence of evidence is not evidence of absence." "There survives nothing" is definitely not synonymous with "there has never been anything written"; since you do not have access to all extant writings, your statement is unsupportable. If the Church destroyed all dissident writing, or buried it in the Vatican library, they (and you) can deny their very existence.
The Catholics have always kept records of the heresies rejected, especially at Councils. (And truths rejected, for that matter.) Even if only keeping their own side, that does survive to record the controversy. This one single issue would be unique if they destroyed or hid not only their oponents' writings, but their own. Yes, in the right circumstances, absence of evidence can be evidence of absence.
Even given the logical errors, you are also factually incorrect (i.e., no records of Christian sects who did not believe in the claims of divinity of Yeshua.) Read about the Ebionites, and get back to me.
I've got an even better one: the Arians, which I forgot completely because I was thinking of very early groups, like the Gnostics (who are condemned by doctrine, but not name, in the New Testament).
So I read about the Ebionites. They seem to have grown out the Judaizers, who I did mention and were very early, but the Ebionites proper, with their low Christology, didn't exist until the second century. They weren't contemporaries of the Apostles.
How accurate do you think those characterizations are? How accurately do they portray Protestantism, for example?