>> they know it happened because people saw him both dying and living afterwards, so it boils down to whether you believe their accounts.

I come from a religious background, born and raised catholic, and even in our indoctrinating upbringing it was made clear that the new testament isn't eyewitness testimony. It's a written story of something someone said. Given the age of the material this is the best we're going to get, obviously, but it's not quite as clear cut as it might seem.

https://en.wikipedia.org/wiki/New_Testament

" They were written between approximately 70 and 100 AD, and were the end-products of a long process of development; all are anonymous, and almost certainly none are the work of eyewitnesses."