Anyone accusing you of “Replacement Theology” is defending the spirit of Antichrist.

[Scott Downey]

I understand all that, but Scripture about unrepentant Israel says :

Rom 11:27 “and this will be my covenant with them when I take away their sins.

Revealed by the Holy Spirit approx 2000 years ago, a covenant with unrepentant Israel, do note.

Furthermore about Israel :

Gal 6:15 For neither circumcision counts for anything, nor uncircumcision, but a new creation.
Gal 6:16 And as for all who walk by this rule, peace and mercy be upon them, and upon the Israel of God.

Paul obviously makes a distinction between the Body of Christ and the Israel of God (Romans 9-11)

Israel is God's business, I don't take sides in the Israel of 1948, I do believe 1948 has God's fingerprints all over it, that the Lord is in control and watch how things will play out, Him keeping the covenant of Rom 11:27.

I therefore have serious doubts Christians can hijack the name Israel.

Well, following your logic, you could then take the position some have done that the New Covenant is only for Israel and not any gentiles, as it says, that God makes the New Covenant with Israel and Judah. No mention of any gentiles. You see what I am saying?

Hebrews 8

A New Covenant​

7 For if that first covenant had been faultless, then no place would have been sought for a second. 8 Because finding fault with them, He says: “Behold, the days are coming, says the Lord, when I will make a new covenant with the house of Israel and with the house of Judah— 9 not according to the covenant that I made with their fathers in the day when I took them by the hand to lead them out of the land of Egypt; because they did not continue in My covenant, and I disregarded them, says the Lord. 10 For this is the covenant that I will make with the house of Israel after those days, says the Lord: I will put My laws in their mind and write them on their hearts; and I will be their God, and they shall be My people. 11 None of them shall teach his neighbor, and none his brother, saying, ‘Know the Lord,’ for all shall know Me, from the least of them to the greatest of them. 12 For I will be merciful to their unrighteousness, and their sins [b]and their lawless deeds I will remember no more.”

13 In that He says, “A new covenant,” He has made the first obsolete. Now what is becoming obsolete and growing old is ready to vanish away.

 

[Scott Downey]

Of the gentiles, Paul teaches that they were brought into the commonwealth of Israel.
This is also the concept of a wild branch (Gentiles) being grafted into the true vine composed of natural branches (Israel)
So that they then are all of Israel, and this of God.
Being of the Israel of God, is a spiritual thing, not a genetic, natural or descendent earthly thing of race.
Believing gentiles are now of the commonwealth of Israel and heirs according to the promises God made to those who are of the true Israel of God.

Ephesians 2

Brought Near by His Blood​

11 Therefore remember that you, once Gentiles in the flesh—who are called Uncircumcision by what is called the Circumcision made in the flesh by hands— 12 that at that time you were without Christ, being aliens from the commonwealth of Israel and strangers from the covenants of promise, having no hope and without God in the world. 13 But now in Christ Jesus you who once were far off have been brought near by the blood of Christ.

Christ Our Peace​

14 For He Himself is our peace, who has made both one, and has broken down the middle wall of separation, 15 having abolished in His flesh the enmity, that is, the law of commandments contained in ordinances, so as to create in Himself one new man from the two, thus making peace, 16 and that He might reconcile them both to God in one body through the cross, thereby putting to death the enmity. 17 And He came and preached peace to you who were afar off and to those who were near. 18 For through Him we both have access by one Spirit to the Father.

Christ Our Cornerstone​

19 Now, therefore, you are no longer strangers and foreigners, but fellow citizens with the saints and members of the household of God, 20 having been built on the foundation of the apostles and prophets, Jesus Christ Himself being the chief cornerstone, 21 in whom the whole building, being fitted together, grows into a holy temple in the Lord, 22 in whom you also are being built together for a dwelling place of God in the Spirit.