So, Christianity is just a religious stew cobbled together from other religions?
Who said that?
Christianity's most prized 'miracles' and events can, however, be found throughout pre-extant mythologies from the same areaa. Start with Gilgamesh and go up through the virgin birth, the resurrection, etc....
Sorry, but they all already existed, and the fact that they are to be found in the bible doesn't detract from the likelihood that they co-opted.