Adam did not decay before the fall - the Tree of Life sustained him.
The forbidden fruit was explained to Adam, not Eve. Gen 2:15-17
Eve was created after from the "rib" Gen 2:21-22
Eve ate first - did the sky fall? no. When Adam ate it, there was an effect.
Gen 3:6And when the woman saw that the tree was good for food, and that it was pleasant to the eyes, and a tree to be desired to make one wise, she took of the fruit thereof, and did eat, and gave also unto her husband with her; and he did eat. 7And the eyes of them both were opened, and they knew that they were naked; and they sewed fig leaves together, and made themselves aprons.
Adam brought sin to the world but Eve was deceived first.
Consider the rhetoric Ecclesiates 3:21, Who knoweth the spirit of man that goeth upward, and the spirit of the beast that goeth downward to the earth?
The answer per Ecc12:7before the dust returns to the ground from which it came and the spirit returns to God who gave it.
For the first 5 days, there was no Image of God until man came along. The body was the vessel of something Holy and was afforded glory (immortality at the Garden of Eden. )
Decay was prevalent in the first 5 days as shown by the fossil records. Eden was endowed with the Tree of Life and decay was rendered meaningless or moot with respect to man. The fall removed access to the Tree of Life, man became part of nature again where decay existed.
The earth means many things.
Consider the literal dirt of the earth.
Eden had fruits to sustain the body in abundance. This allowed Adam to commune with everything and most of all God. What hunter-gatherer tribe created any advanced civilization? None that I can think as It cannot because there is no leisure time to do other things. What about the modern society? Not a good situation either It is said that were are 10 meals from chaos if the logistical trucking system ever collapsed (based on walmart supercentres). We are seeing the failure of shipping system because of COVID ( JIT logistics - no storage). California is a seeing a drought that might last for years - the bread basket of the west( no storage of surface water were built because they thought climate change would render it useless) . The funny thing is all this stems from the knowledge of man. The dirt of the earth is cursed because we listen to the wisdom of man. We can not sustain the earth and sea and in turn it cannot sustain us.
Consider as ancestral soil from which we spring. Gen 2:7 the soul = breath of life + soil of the ground. The breath of life is God's (Gen 7:22, Prov 20:27, Isa 30:33). The soil is the remaining ingredient. The substance apart from God's breath is cursed. Consider Genetic Entropy: John C. Sanford (he is a Christian) He plotted the life span of all the patriarchs with time and found it followed a decaying curve. The DNA of mankind is slowly degenerating. Scientist say that we acquire ABOUT 40 mutations a generation - all of them detrimental (1 in 10000 is beneficial). Without the Tree of Life, mankinds genome will decay till we are extinct. The natural state of man.
Adam's physical world was 2 persons. The Spirit of God gave 1 condition to the Adamic covenant. He broke it because of Eve. We live with multiple distractions.
Romans 8:1-3 reiterates the yoke of Christ is light Matthew 11:30.
Romans 8:4-8 The covenant as per Mark 12:30-31 can only be fulfilled if we obey the Spirit of God. If you obey the man's doctrines, you will end up with 2 masters Matthew 6:24, hating one over the other. Considerations of the flesh (i.e. Adam and Eve with the fruit) can never ultimately fulfill your obligations to God. Render all Glory to God, the rest will fall in place.
Scripturally, Jesus is the Branch of Jesse (Isaiah 11) and Scion of David (Jeremiah 23:5).
The Branch of Jesse was from the mother Mary.
As Joseph was of Judah (Luke 2:4) but was forbidden (Jeremiah 22:30), the scionship came from God.
Legally and prophetically it was necessary.
He is the literal Son of God and the son of David (God smeared David and David begat Jesus)
As a conjecture, how else can you fit an intellect and power like the Word. You need a perfect body. The DNA had to be completely rewritten.