Earl Doherty makes a convincing case in The Jesus Puzzle that Paul thought Jesus died and was resurrected in a lower heaven, not in history on earth. The evidence is mixed, as is usually the case with regard to historical questions. But the evidence is far from clear-cut in favour of the historicist view.
Paul's letters get filtered through the Gospels, especially in English translations. He was far more Gnostic and spiritual or mythic than most Christians realize. Paul says he got his gospel from scripture and from a special revelation from the risen Jesus, not from any man and therefore not from history (Gal.1:11-12; 1 Cor.15:3-4)). That was a very strange thing to say if Jesus had lived recently on earth.