You keep jumping between folklore as recorded in the Book of Jubilees and Genesis, which is the word of God.
What was the function of the river and Tree of Life in Garden of Eden? The river watered the land and the Tree of Life was so man could live forever.
Genesis 3:22-24
22 Then the LORD God said, "Behold, the man has become like one of Us, knowing good and evil; and now, lest he stretch out his hand, and take also from the tree of life, and eat, and live forever"-- 23 therefore the LORD God sent him out from the garden of Eden, to cultivate the ground from which he was taken. 24 So He drove the man out; and at the east of the garden of Eden He stationed the cherubim, and the flaming sword which turned every direction, to guard the way to the tree of life.
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However, neither the river or the Tree of Life are the focus of God's word; the Messiah and what we need to know concerning eternal life are the focus of God's word.
What are the rivers of living water?
Jeremiah 17:13
13 O LORD, the hope of Israel,
All who forsake Thee will be put to shame.
Those who turn away on earth will be written down,
Because they have forsaken the fountain of living water, even the LORD.
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John 4:10
10 Jesus answered and said to her, "If you knew the gift of God, and who it is who says to you, 'Give Me a drink,' you would have asked Him, and He would have given you living water." NAS
John 4:11-14
11 She said to Him, "Sir, You have nothing to draw with and the well is deep; where then do You get that living water? 12 "You are not greater than our father Jacob, are You, who gave us the well, and drank of it himself, and his sons, and his cattle?" 13 Jesus answered and said to her, "Everyone who drinks of this water shall thirst again; 14 but whoever drinks of the water that I shall give him shall never thirst; but the water that I shall give him shall become in him a well of water springing up to eternal life. " NAS
John 7:38
38 "He who believes in Me, as the Scripture said, 'From his innermost being shall flow rivers of living water.'" NAS
The geographical location of the Garden of Eden is immaterial to our walk with the Lord.