Genesis is completely pertinent to eternity and the life and resurrection of Jesus.
Paul refers in his writings to the first Adam and the second Adam. He says in Romans 5:12 that through one man (Adam) sin entered into the world. It is the second Adam (Jesus) who came to destroy the works of the devil (1John 3:8)
If Adam isn’t a historical figure, then Christ came, lived a sinless life and died a horrific death based on a “creation myth”.
Jesus himself said in Matthew 19:4-5 and a parallel passage in Mark 10:6: “Have you not read that in the beginning, God made them male and female”.
If you are a disciple of Christ you should trust in what He said.