I don't think He meant (in John 3) that during the millennial kingdom all the saints will be invisible vapors or breezes invisible to everyone, yet heard.
To say that this being born of the Spirit cannot take place in the church age is wrong.
John tells the Christians that everyone who believes in Christ has been
BEGOTTEN of God. And that is REGENERATED and BORN OF THE SPIRIT.
" Everyone who believes that Jesus is the Christ has been begotten of God, and everyone who loves Him who begets, loves him who has been begotten of Him." ( 1 John 5:1)
1.) If what you teach is true then no one has been begotten of God until the millennial kingdom.
2.) If what you teach is true then no one believes that Jesus is the Christ until the millennial kingdom.
3.) If what you teach is true then no one loves others having also been begotten of God until the millennial kingdom.
4.) If what you teach is true then John means -
"Everyone who enters the millennial kingdom after the second coming of Christ is begotten of God. . And that would mean that no one in the church age is begotten of God.
Your wrong teaching postpones all new birth from the Holy Spirit until after the start of the millennium. But John says there the believers can know TODAY that God has given to us of His Spirit - ie. "born of the Spirit" :
" In this we know that we abide in Him and He in us, that He has given us of His Spirit." ( 4:13)
Paul also tells the Galatians the God, in that present church age then, before the millennium was supplying to them the Holy Spirit -
" He therefore WHO IS supplying to you the Spirit, DOING works of power among you, is it by the works of law or by the hearing of faith?" (Gal. 3:5)
In the church age God is
SUPPLYING [present tense]
"the Spirit" to those born of the Spirit before the millennium.
And Paul says that they ARE on this side of the millennial kingdom -
"sons of God" crying Abba Father by the indwelling Holy Spirit.
"And because you are sons, [not WILL BE sons if you WAIT until the millennial kingdom] God sent forth the Spirit of His Son into our hearts, crying, Abba Father !" (Gal. 4:6)
ABBA! -
PAPA - DADDY to God - because they are
born of God - regenerated to be His children and even His sons.