The Anonymous Gospel Manuscripts

[Aractus]

With respect to the OP, none of the Gospels show up until at least the second century, ...

No that's not true, they show up no later than the second century, and almost certainly before the end of the first century. There are no serious scholars who date the Synoptics any later than 90AD. P66 & P75 were both written around 200AD, both clearly contain the "gospel according to John" titles like this:



And importantly, as they both contain the Gospel of John we also know they represent two separate textual traditions (though both a part of the Alexandrian text-type). Thus you have to allow time for both textual traditions to be independently circulated to an extent that we might later find them - scholars say this should represent at least 30-40 years otherwise the probability of finding a surviving papyrus manuscript with a differing textual tradition is impossibly implausible. Thus it suggests that the separation from convergence had to be around 170AD or earlier.