Another reason why I think the question of Jesus’s historicity doesn’t matter for philosophical purposes, however interesting that question may be historically, is that the evidence is far too ambiguous to make a decisive case either way. And the only Jesus that’s plausibly historical poses no challenge to naturalism, secular humanism, or the other philosophies I espouse.

You’ve weaved an elaborate conspiracy theory here about what the historical Jesus would have been like. Again, it can be fun to speculate on what might have happened in the distant past, but when the evidence is so weak and ambiguous, we can’t put much stock in any such scenario. Jesus might have survived crucifixion in a non-supernatural way, but such an event would have been highly improbable, given how the Romans worked. The more elaborate the conspiracy theory, the more dubious it is in violating Occam’s razor.

I agree that if Christianity were founded on some such fraud, that would be philosophically rather than just historically interesting. But on epistemological grounds, we can’t trust that any such conspiracy happened without sufficient evidence. If the evidence were so clear, we’d have to account for why most historians don’t take such a strong stand on the issue (or even give it the time of day). We’d have to expand the conspiracy by pointing to an ongoing institutional fraud. The simpler explanation is that the evidence for the ancient conspiracy isn’t so strong.

Once you dismiss the Christ of faith as ahistorical, I don’t think it matters much what exactly the historical Jesus said or did. If you want to show that Christianity perpetrated a fraud, you need merely point to the Church’s promotion of the Christ of faith. There’s no need to adduce a coverup of an inconvenient historical Jesus, to show that Christian institutions have been hypocritical and grossly in error.