Yeah, I understand where you're coming from, which is why I'm citing historical analysis of the Bible. Most scholars don't think King Arthur was real, and if he was, the stories weren't written when he was alive, so you can't put any stock in the story because no witnesses were around to verify nor dispute it. On the other hand, even if you believe the Bible is a book of myths, there are still historical facts that have been independently verified, like:

• There was a guy named Jesus who got crucified^[https://en.wikipedia.org/wiki/Tacitus_on_Jesus]
• The disciples were real people^[https://old.reddit.com/r/AskHistorians/comments/1qn6r4/are_there_any_historical_proof_that_all_12/]
• Paul's letters (or at least most of them) were written by Paul while he and at least some of the disciples were still around^[As previously cited]
• The early church was significant and persecuted^[Tacitus again]

Because the early church was significant and the disciples were real people, I conclude that they were famous.
Because they were famous, I conclude that if they said anything surprising, word would have gotten around.
Because Paul's letters were written while the disciples were around, and the disciples were famous, I conclude that if he said anything surprising about the disciples, they would have heard about it.
If the disciples heard a story about them that never happened, they would have confirmed it, denied it, or evaded the question.
If they confirmed a story, that doesn't necessarily mean it's true, but it does mean they wanted people to believe it's true.
If they denied a story, that would have been surprising, and word would have gotten around, so there would have been some mention somewhere.
If they evaded commenting on a story, that means they wanted people to believe it's true (and hints that it was untrue, but that part doesn't really matter for my purposes here.)
Thus, if Paul wrote something about the disciples while they were around, and there's no mention anywhere of them denying it, that indicates that the disciples wanted people to believe it's true.

Paul wrote about Jesus appearing to the disciples after resurrection, and there's no mention of them denying it. This doesn't necessarily mean that the resurrection was true, but it does mean that the disciples were at least complicit and refused to deny it even in the face of persecution. As for conclusions from there, see my earlier comment.

Is that line of thinking solid enough, depending on historically verified facts instead of taking the Bible as an accurate account at face value?

Also, something that bugged me about your earlier comment: You say you make no claim as to whether a god exists, you just aren't convinced. And you say there's no proof for a lack of a god. Yet you also said that you think aliens causing the resurrection (or appearance thereof) is more plausible than a god existing.

Aliens having the technology, knowledge, and motivation to cosplay as God is already highly unlikely, whether in a world with a real god or not. Jesus being the real deal is fairly likely if in a world with God, but impossible if in a world with no god.

So if you're telling me that Jesus being the real deal is less likely than aliens cosplaying God, that tells me you think there being no god is significantly more likely than God existing. In the absence of evidence in either direction, they should be treated as equally plausible (though not equally valid, as burden of proof is still a thing.) The fact that you don't tells me you actually do lean towards the lack of a god.

Not that there's anything wrong with that. I'm definitely biased towards God existing. I'd just like you to introspect and examine your bias so you're aware of it. Though I'd also appreciate it if you adjusted your parameters and leaned a little more this way ; )