No, I'm not saying anything like that.
What I am saying is this:
If you sow dead seeds, nothing will come to life. But in the sense that Jesus and Paul used the world, "die" means to change state. So of course the seed has to stop being a seed in order to become a plant.
Earthly bodies can be sinless. After baptism, an earthly body is sinless. After confession and absolution, an earthly body is sinless (assuming the confession has been truthful). Little children who have been baptized and have not yet done any moral wrong are sinless (it's why we need to become like little children to enter the Reign of God). But while we CAN be, we're generally not most of the time.
The body is just a vessel of dirt. The thing that bears the sin forward is the spirit. The only consequence of sin to the body is that it turns back into dirt, but the spirit has the opportunity for immortality, or damnation and utter destruction.
Everybody doesn't become sinless after death. People bear their sins INTO death, and, unless those sins are forgiven, they pay for them there.
Actually what makes a seed alive is burial. In other words a seed is useless, dead, unless it is buried:
John 12:
24I tell you the solemn truth, unless a kernel of wheat falls into the ground and dies, it remains by itself alone. But if it dies, it produces much grain.
25The one who loves his life destroys it, and the one who hates his life in this world guards it for eternal life.
26If anyone wants to serve me, he must follow me, and where I am, my servant will be too. If anyone serves me, the Father will honor him.
It seems that burial is what happens when a person converts. Leaving Egypt's mindset and being buried into Moses' mindset:
Hrbrews 11:
24By faith, when he grew up, Moses refused to be called the son of Pharaoh’s daughter,
25choosing rather to be ill-treated with the people of God than to enjoy sin’s fleeting pleasure.
1 Corinthians 10:do not want you to be unaware, brothers and sisters, that our fathers were all under the cloud and all passed through the sea,
2and all were baptized into Moses in the cloud and in the sea,
3and all ate the same spiritual food,
4and all drank the same spiritual drink. For they were all drinking from the spiritual rock that followed them, and the rock was Christ.
Would you agree that making the seed alive requires it to die, turn it from serving the world, bury itself in Christ, serve Christ?