As explained many times before, I see it as the best explanation for the empty tomb (after Jesus was killed by crucifixion), for people as individuals and groups on about a dozen known occurrences being convinced that they met him right as ninepence in the following days and for the start of the Christian church by a bunch of previously dispirited, defeated people.
How do you know that the 'empty tomb' aspect of this story isn't pure fiction?
Because all the authorities had to do do disprove it was point people to Jesus' body in the tomb if it was not empty.
It is that simple.
You are assuming that the 'empty tomb' element was an issue at the time of the alleged resurrection: but that the tomb was empty and that the body of Jesus was there at all are claims and not facts. So, how to you
know that this isn't just a later addition by Jesus supporters at the time the story was first written down decades later?
After all propaganda is a risk, and if you can't acknowledge this then you are indulging in special pleading that those early Christians/NT writers were immune from human artifice in support of their cause.
If there is a risk that it isn't true at all, and there is this risk, then your challenge to 'explain' these claims is spurious since your challenge involves assuming that claims are facts, and I'd say that such assumptions are unjustified.