Mark

‘Is Paul contradicting Jesus? Jesus calls them sick. And His words are recorded twice. Where is a second witness that sinners are “dead” and in need of a resurrection?’

I’m not sure why you are trying to play Jesus words off against Paul as if the red letter parts of the bible are more authoritative. But just so you are aware here is a second witness to being dead in sin apart from Eph 2:1

Col 2:13 And you, who were dead in your trespasses and the uncircumcision of your flesh, God made alive together with him, having forgiven us all our trespasses,

John 6 sounds great. What parts? What have you got in mind?