The Gnostic gospels were only relatively recently discovered (1945 per Wikipedia), perhaps I should have picked one of the other heresies in early Christianity

The Gnostic gospels were only relatively recently discovered (1945 per Wikipedia), perhaps I should have picked one of the other heresies in early Christianity that are virtually unknown outside of some early church father dismissing them. And my point isn't that oral records are better than written records, it's that they're not really worse. Or put differently, written records are rather incomplete accounts: there's a tendency to treat written records as the ground truth of history which isn't particularly warranted.