For a number of reasons people miss the continuity in the New Testament narrative between the pre- and post-resurrected Christ. The New Testament does not make the appearances of the risen Jesus any less historical than the ministry of the pre-risen Jesus. For sceptics the constrast in the pre-/post- resurrected narrative is between history (no matter if exact details of the ministry of Jesus are disputed) and the non-historical resurrection appearances. This leads to all kinds of psychological/spiritual explanations of the appearances of the resurrected Jesus. I can't see it in the text myself, and seems to me an alien preconception forced onto the text. The resurrection appearances as narrated in the New Testament are to be thought of as history-like. (e.g. Ac 2:23-24)
Does the New Testament encourage us to entertain a contrast within the story of the life, death and resurrection of Jesus? Yes, and it revolves around the enormity of the rejection of Jesus, and specifically his desolation on the cross. The God before the cross is not possible to believe in. The Father delivered up the Son; in reality, and this is deeply shocking, even to Jesus himself. Who is the resurrected Christ and the God who raised him? is belief even possible after the cross? If the resurrection is not merely the cancellation of the cross, but includes it (remembering that resurrection has nail holes in it), who is God? The answer to that question makes Christianity possible, and stands in contrast to ordinary religion. this is the contrast the new Testament is asking of us.