This all seems somewhat semantic to me.
As you say, death does not equal non-existence but rather a separation. Physical death is the separation of our soul/spirit from our physical body. Spiritual death is the separation of our soul/spirit from God.
Our
spirit belongs to God, "Who gave it". Ergo, all
souls belong to Him while they remain united with the
body. When our body dies, mans spirit returns to Him.
Granting that, then a man who is dead in sin (i.e. separated from God) is brought to new life in Christ upon believing the gospel and placing his faith in the finished work of Christ on his behalf. How is that not "granting eternal life"?
Conditionally, yes.
John 17:3 And this is eternal life, that they may know You, the only true God, and Jesus Christ whom You have sent.
That certainly is a condition, isn't it? However, it is spoken by Jesus to imply intimacy with God and Himself.
Romans 7:9 I was alive once without the law, but when the commandment came, sin revived and I died.
Yes meaning the intensity of the power of the law of Paul's flesh, increased. Spiritual warfare had begun. You should understand that if you are a Christian.
1 Corinthians 15:21 For since by man came death, by Man also came the resurrection of the dead.
Yes. For since by man, without God indwelling him, came death, by man also, with the indwelling of God, came the resurrection of the dead.
Philippians 3:8 Yet indeed I also count all things loss for the excellence of the knowledge of Christ Jesus my Lord, for whom I have suffered the loss of all things, and count them as rubbish, that I may gain Christ 9 and be found in Him, not having my own righteousness, which is from the law, but that which is through faith in Christ, the righteousness which is from God by faith; 10 that I may know Him and the power of His resurrection, and the fellowship of His sufferings, being conformed to His death, 11 if, by any means, I may attain to the resurrection from the dead.
Certainly the resulting evidence of one who is born again and on his agape road journey, seeking to know God and Jesus Christ Whom He has sent, . . . . to Father's House..