Your excellent study on the book of Revelation makes the point that there is no need for the church to eat from the tree of life. The tree of life is for the nations during the millennium. If this is so, why does Jesus promise that believers will “eat from the tree of life” in Revelation 2:7?
In Rev. 2:7, eating from the tree of life is a euphemism for having eternal life. It comes from Genesis 3:22-23 where we learn that the reason Adam and Eve had to be kicked out of the Garden after they sinned was to prevent them from eating of the tree of life, which would have given them eternal life as sinners. This is something God could not allow.
In the same way, those who rely even partially on their own works to earn or keep their salvation are saying they don’t believe Jesus did the whole job of saving them at the cross. Believing they have to “make up the difference” with their own effort means they think they’re saving themselves. Those in Ephesus who overcame the temptation of falling into a works based life and relied solely on the Lord for their salvation would be given eternal life. This implies that those who don’t rely fully upon His completed work are not saved.
Also, the purpose of the tree of life in the Millennium is for healing the people on Earth (Rev. 22:2). In the New Jerusalem, home of the Church, there will be no more death or mourning or crying or pain (Rev. 21:4). In other words, no need for healing.