"These are just some of the reasons why we cannot trust extraordinary reports from that time without excellent evidence, which we do not have in the case of the physical resurrection of Jesus. For on the same quality of evidence we have reports of talking dogs, flying wizards, magical statues, and monsters springing from trees. Can you imagine a movement today claiming that a soldier in World War Two rose physically from the dead, but when you asked for proof all they offered you were a mere handful of anonymous religious tracts written in the 1980's? Would it be even remotely reasonable to believe such a thing on so feeble a proof? "
Which brings us to the second point: it seems distinctly possible, if not definite, that the original Christians did not in fact believe in a physical resurrection (meaning a resurrection of his corpse), but that Jesus was taken up to heaven and given a new body--a more perfect, spiritual body--and then "the risen Jesus" was seen in visions and dreams, just like the vision Stephen has before he dies, and which Paul has on the road to Damascus. Visions of gods were not at all unusual, a cultural commonplace in those days, well documented by Robin Lane Fox in his excellent book Pagans and Christians. But whatever their cause, if this is how Christianity actually started, it means that the resurrection story told in the Gospels, of a Jesus risen in the flesh, does not represent what the original disciples believed, but was made up generations later. So even if they did die for their beliefs, they did not die for the belief that Jesus was physically resurrected from the grave.
That the original Christians believed in a spiritual resurrection is hinted at in many strange features of the Gospel accounts of the appearances of Jesus after death, which may be survivals of an original mystical tradition later corrupted by the growing legend of a bodily resurrection, such as a Jesus that they do not recognize, or who vanishes into thin air. But more importantly, it is also suggested by the letters of Paul, our earliest source of information on any of the details of the original Christian beliefs. For Paul never mentions or quotes any of the Gospels, so it seems clear that they were not written in his lifetime. This is supported by internal evidence that suggests all the Gospels were written around or after the destruction of Jerusalem in 70 A.D., well after Paul's last surviving letter, which was written around the year 58.
Yet Paul never mentions Jesus having been resurrected in the flesh. He never mentions empty tombs, physical appearances, or the ascension of Jesus into heaven afterward (i.e. when Paul mentions the ascension, he never ties it to appearances in this way, and never distinguishes it from the resurrection event itself).
https://infidels.org/library/modern/richard_carrier/resurrection/lecture.html