this all leads to questions on what/who The Church is, if it’s to be structured as an apostolic succession, if that succession holds a certain Automatically Right stature regardless of its actual conduct, and so on.
Apostolic succession is something that originally served a very practical purpose; to distinguish true from false teachers. Orthodox Christians could tell you exactly where their teachings came from, all the way back, because it had only been a couple of generations, whereas the gnostic heretics had to claim it was “secret” and that’s why you couldn’t trace it.
There are diminishing returns on that, though. It makes sense when your teacher directly knew an apostle, but once you get past 3rd generation, it becomes harder and harder to verify where things have mutated, especially because each new bishop is ordaining potentially dozens of new bishops in his lifetime.
Apostolic Succession as a necessary mark of the Church is foreign to the Apostolic Fathers. It’s a corruption. As for what the Church is, the Greek word is just ecclesia. If there is a body of true Christians with a hierarchy, that’s the Church. The thing that separates true from false is whether they worship Christ. But Nestorians, for example, are not the Church, because they don’t worship the real Christ. The atonement doesn’t make sense if he’s just a spirit in a skin suit.
we’re getting third hand … texts that have gone through who knows how many rounds of editing, reconstruction, compilation, and who knows what else…
That definitely didn’t happen for the New Testament, because both the text and the Church were decentralized. There’s no recorded event like the revision of the Quran, it was just distributed and copied in different locations. The only “revisions” were after the Christianization of Rome, minor variants from different manuscripts in the empire were synthesized to agree with one other. But we also have large manuscripts from outside the empire, and prior to the synthesizing. We already know what it looked like before then, and it’s barely different at all.
You have more of a case in the Old Testament, because it’s more clearly a series of composite documents and we don’t know exactly where it came from. It doesn’t take a Hebrew expert to realize the vocabulary changes vastly between different places, even within the same book. There’s also the problem of the Masoretic vs the Septuagint, and older Hebrew variants agreeing with the Greek. But the Greek is often paraphrase, so you can’t use it as a primary source either.
It’s fucked, but one thing we can trust is that the New Testament, which has a much stronger proof, presupposes the accuracy of the Old Testament, and even though Old Testament variants are broader than New Testament ones, we still don’t have anything that deviates all that much. Except in cases where it varies so much that it doesn’t even constitute the same book, like Jubilees, or the Dead Sea Scrolls version of Genesis and Exodus.
Even with all that evidence, there’s not necessarily any sign of deliberate tampering prior to the split between jews and Christians. The composite nature of the document can be attributed to the loss of Old Hebrew as a language in late antiquity. We can presuppose that there is genuine editing, or that there isn’t. I trust that if there was, we would know about it. Christ or one of the Apostles would have told us.