I don't think its a scam. Jesus didn't write about himself, others wrote about him.
Multiple sources and witness accounts.
And the ultimate is why on earth would Jesus willingly suffer for something he didnt truely believe 100% was truth when he could have easy walked away and lived a normal life he was given many opportunities, why would Paul eating well living a good life in a position of Authority humble himself and willingly put himself in chains and recieve beatings if it was or even maybe could have been a lie. He could have continued living a good life yet he willingly suffered for what he claimed he seen.
Why would the disciples willingly suffer for a scam. When after Jesus died they could have just moved on with there life. It was only the claim of his ressurection and what they seen did they believe and willingly suffered for it and took it to there graves. I don't think as eye witnesses they would do that for a lie or some sort of joke or hoax.
It's not like 1 individual wrote the gospel, it's multiple eye witness and second witness accounts that add up.