Let me guess...you think "nation" refers to Gentiles? How wrong you are.
Scripture refers to Israel as a nation. It's used generically not specifically.
"Nations" came out of Abraham. So did kings. But you seem to forget Ishmael had twelve princes and Esau had descendants that were referred to "nations" and this seed of Abraham did not mean Gentiles in Genesis 17 and it doesn't mean Gentiles in Matthew 21.
Natural Olive tree Israel was a nation among nations. Their nationhood took on another meaning when God began redeeming His people and through the Holy Spirit of Promise PROMISED TO ISRAEL - AND SCRIPTURE CANNOT BE BROKEN - The Jews became spiritual Olive tree Israel, a whole new nation came into existence through the new birth of Jews by the Holy Spirit of Promise PROMISED TO ISRAEL.
You keep trying to add Gentiles into the Hebrew covenants after the fact and ignore that to add Gentiles into the Hebrew covenants violates and breaks Scripture because when the Hebrew covenants were being made between God and the Hebrew people no Gentiles are named or mentioned when these covenants were being made.
Its over for national israel, the Covenant Privileges were taken away and given to the Gentiles, but ethnic jews will still be saved as they are now part of all nations, no distinction :
National ethnic israel
has lost its Covenant distinction with God, jews now are saved as part of the Gentile nations, as God is calling the gentiles some ethnic jews are being called.
Matt 21:33-43
33 Hear another parable: There was a certain householder, which planted a vineyard, and hedged it round about, and digged a winepress in it, and built a tower, and let it out to husbandmen, and went into a far country:
34 And when the time of the fruit drew near, he sent his servants to the husbandmen, that they might receive the fruits of it.
35 And the husbandmen took his servants, and beat one, and killed another, and stoned another.
36 Again, he sent other servants more than the first: and they did unto them likewise.
37 But last of all he sent unto them his son, saying, They will reverence my son.
38 But when the husbandmen saw the son, they said among themselves, This is the heir; come, let us kill him, and let us seize on his inheritance.
39 And they caught him, and cast him out of the vineyard, and slew him.
40 When the lord therefore of the vineyard cometh, what will he do unto those husbandmen?
41 They say unto him, He will miserably destroy those wicked men, and will let out his vineyard unto other husbandmen, which shall render him the fruits in their seasons.
42 Jesus saith unto them, Did ye never read in the scriptures, The stone which the builders rejected, the same is become the head of the corner: this is the Lord's doing, and it is marvellous in our eyes?
43 Therefore say I unto you, The kingdom of God shall be taken from you, and given to a nation bringing forth the fruits thereof.