I can't think of any veritable Jew who would call the totality of his heritage σκυβαλα (shit, rubbish, dung, excrement, waste, slime) (Phil.3:8). Nor can I imagine any scholars doing him a favor by focusing on those aspects of his past that he himself considers worthless as if those very aspects were THE MOST IMPORTANT ASPECTS. Once again, behold the sheer stupidity of the modern scholar!
Paul is not a Jew. He is no more a Jew than I am a Mennonite, though I come from that background and flit about a few vestiges of its cultural σκυβαλα.