From sources hundreds of years later, second or third hand quoting (mostly) illiterate witnesses, with a vested interest in telling a compelling and believable (for the era) narrative. Also, most of the adjacent claims from said sources cannot be proven or similar miracles reproduced, despite claims such events will be common given "faith as small as a mustard seed".
Book of Mormon was written during Smith's lifetime. I still don't believe he talked to angels or actually got divine revelation from golden plates.
As for the rest of your complaint: Luke is demonstrably a good historian. He is also very careful. (One thing I notice that amuses me: In Acts, sometimes Luke is traveling with Paul. When he is, the level of detail goes up. Not "Then Paul departed from X, and went to Y", but "Then we got on a ship, and sailed to A. On the next day we sailed to off of B. Then we passed on side C of island D..." Luke knows what he knows, and he's not filling in detail when he doesn't know it.)
I'm not going to defend Joseph Smith or the Book of Mormon at all. I also don't know why you brought them up.
Just because an account is detailed doesn't mean everything it describes happened.
Jesus supposedly even claims prophets get no respect in their own town. Which is entirely consistent with how conmen are treated.
Which is why they are fantasy. In order to "actually happen" there must be observable change. And despite mighty efforts there is no physical evidence that defies simpler and more reproduceable explanations.
It takes believing in the AI singularity. I mean, sure, once it happens (if it does), then you won't have to "believe" in it, because it will be real and present right in front of you. If it happens.
Which in some ways is really similar to the return of Christ. If/when it happens, it won't take "faith" or "belief" any more.
But before either happens, believing in the AI singularity, at least to me, takes more faith than believing in the return of Christ. At least with Christ, I've got a (documented) resurrection to lean on. With AI, I've got a surge of progress in the last few years, and a history of AI winters after progress slows back down, and people realize that the last burst of progress isn't going to get us to an AGI.