The details of the New Jerusalem are of Christ, yes. But they are of Christ wrought into His people. For it is Christ imparted into the save which the Triune God ever operates for.
His purpose for the saints in Romans 8:27-29 was already revealed.
Foreknew ---> Predestinated ---> Called --->Justified ---> Conformed -->Glorified
Ephesians 1:21 speaks of the great "far above all" exaltation of Christ. And that throughout all the ages to come. He is the Head of His Body. The saved are the Body of the Head. And the following verse says it is "to the church" He transmits this eternal Headship.
And He subjected all things under His feet, and gave Him to be Head over all things to the church, (v.22). Then in verse 23 we see this organism (not organization), but this living organism,
is filled with Christ who fills all in all. All regenerated believers have thier destiny to enjoy Christ's riches for the expression and activites of the Head. "He . . . the Head over all things to the church which is His Body the fullness of the One who fills all in all. (v.22b,23)
Be cause the Head transmits "to the church" His Body His life, nature, and expression there is for eternity - "the glory in the church and in Christ Jesus unto all the generations of the age of the ages. Amen" (Eph. 3:21)
In fact the Triune God is able to do superabundantly this above not only all we could ask but even what we could think. "But to Him who is able to do superabundantly above all that we ask or think according to the power which operates in us." (Eph. 3:20)
Christ "came down" also. But He did not leave God when He came down. He brought God with Him. "I am the living bread which came down out of heaven;" (John 6:51a)
This does not mean Christ came down as if by helecoptor or escalator or parachute or ladder. It means He came down by way of His incarnation. He came from the Father in the way of coming [from with] the Father bringing the One who sent Him along with Him. And He who sent Me is with Me; He has not left Me alone, for I always do the things that are pleasing to Him. (John 8:29)
So Christ is the inacarnation of God in a man, And He came down by way of incarnation that we might "eat" Him - that is to take Him in in order the God may live in us and we in Him.
As the living Father has sent Me and I live because of the Father, so he who eats Me, he also shall live because of Me. (John 6:57)
Christ came down by incarnation. The church and the New Jerusalem come down by way of the Triune God dispensing Himself into man.
No, the marriage of Jesus is the more real marriage towards which all human marriages are a symbol. You have it exactly backwards. The MORE real marriage is that of Christ and the church. All other marriages in the universe point in allegory to THIS marriage.
In fact, Christ is the more real reality of all positive things in creation.
The sun you see is not the real sun, in this sense. Christ is the real sun.
Christ is the real life, the real earth, the real atmosphere, the real brooks and streams.
As for uman marriage, Christ's union with His redeemed people is the more real marriage towards which all other marriages are a pointer.
All other positive things are a shadow of Christ who is the body os the shadow and the more real substance and "body" of positive things. Even the reituals ordained in the OT.
Let no one therefore judge you in eating and in drinking or in respect of a feast or of a new moon or of the Sabbath, Which are a shadow of the things to come, but the body is of Christ. (Col. 2:16,17}
You are mistaken to lift Israel higher than the New Jerusalem. For the church walking and living by the Spirit in the new creation, Paul says is "the Israel of God." She is not second class to the theocratic nation. Galatians 6:15,16 -
For neither is circumcision anything nor uncircumcision, but a new creation is what matters.
And as many as walk by this rule, peace be upon them and mercy, even upon the Israel of God.
"The Israel of God" includes the Galatian churches IF they would be brought into this new creation and walk by the Spirit. And these were Gentiles. As many (from either Jews or Gentiles) who thus walk, are collectively this Israel of God. And as many as walk by this rule, peace be upon them and mercy, even upon the Israel of God.
In the end of the ages the Spirit and the Bride speak TOGETHER. For the Spirit IS the Bridegroom LIVING WITHIN the Bride. So utterly into union and oneness God brings the church with the Spirit that they eventually speak as one.
And the Spirit and the bride say, Come! And let him who hears say, Come! And let him who is thirsty come; let him who wills take the water of life freely. (Rev. 22:17)
The Spirit and the bride means the Bridegroom and the Bride.
The Bridegroom has become the life giving Spirit to indwell His people, fill and saturate His people unto mingling of God and man. It is written "the last Adam [Christ] became a life giving Spirit." (1 Cor. 15:45b)
The work of Redemption is soley His. But the Redeemer wroughts His life and nature into His wife, the church / New Jerusalem. The life giving Spirit [Christ the Bridegroom] is dispensed into His counterpart. This is why human beings are forgiven, re-born, sanctified, transformed, built up together in life and love in resurrection and in glorification. This is the eternal purpose of God.