every man must die for his own sin, He can not die for another mans sin, because he is guilty of sin himself. It takes an innocent person to die for the sin of another.
That is what the sacrificial system taught. That an innocent had to shed his blood for the sins of the guilty.
So if Jesus was guilty of sin Your right, he could not die for anyone else's sin, but only his own, and he will end up in eternal darkness, because even his physical death could not restor him to God,
But if he was perfect. He could die for someone else's sin, and as God, he could die for everyone else's sin. and only as God could he die the proper death in order to redeem everyone else to God.