The sentence passed on Adam and his progeny is that they would corrupt back into the dust.
Genesis 3:19 In the sweat of thy face shalt thou eat bread, till thou return unto the ground; for out of it wast thou taken: for dust thou art, and unto dust shalt thou return.
Cremation is just a faster way of returning the body to dust.
Whether the dust is deposited in a coffin in the ground, or in a sepulchre or an urn, or is scattered into the sea is immaterial as far as scripture is concerned.
What does matter is that if we want eternal life instead of eternal death, we must believe and obey the gospel preached by Jesus Christ and his apostles. Those who believe and obey will be raised from their death state and given eternal life in the kingdom of God.
Believing and obeying involves baptism.
I hope you find this helpful.