Gentile means any nation that is not israel
so consider this scripture
“And this gospel of the kingdom shall be preached in all the world for a witness unto all nations; ( gentiles ) and then shall the end come.”
Matthew 24:14 KJV
Another way to say that is gentiles are all creators of earth not of the old covenant chosen and seperated people ( the children of Israel )
“And he said unto them, Go ye into all the world, and preach the gospel to every creature. ( gentiles ) He that believeth and is baptized shall be saved;
but he that believeth not shall be damned.”
Mark 16:15-16 KJV
after the kingdom is preached to everyone the king will return at the end of the world
“When the Son of man shall come in his glory, and all the holy angels with him, then shall he sit upon the throne of his glory: and before him shall be gathered all nations: and he shall separate them one from another, as a shepherd divideth his sheep from the goats:
Then shall the King say unto them on his right hand, Come, ye blessed of my Father, inherit the kingdom prepared for you from the foundation of the world: for I was an hungred, and ye gave me meat: I was thirsty, and ye gave me drink: I was a stranger, and ye took me in: naked, and ye clothed me: I was sick, and ye visited me: I was in prison, and ye came unto me. …And the King shall answer and say unto them, Verily I say unto you, Inasmuch as ye have done it unto one of the least of these my brethren, ye have done it unto me.
Then shall he say also unto them on the left hand, Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels: for I was an hungred, and ye gave me no meat: I was thirsty, and ye gave me no drink: I was a stranger, and ye took me not in: naked, and ye clothed me not: sick, and in prison, and ye visited me not.
Then shall he answer them, saying, Verily I say unto you, Inasmuch as ye did it not to one of the least of these, ye did it not to me. And these shall go away into everlasting punishment:
but the righteous into life eternal.”
Matthew 25:31-32, 34-36, 40-43, 45-46 KJV
you can see how anyone and everyone is welcome now all gentiles and Jews are welcome in the new covenant when the time comes jesus will return and fether his people not based on whether they were born an Israelite by human blood , but based on whether they are born of Gods spirit through Christ nd how they treated others
Your asking when is the time God will stop accepting any person based on what they believe and not what thier flesh and blood says about them
A gentile just means any non israelite by geneology any person on earth regardless of nationality or blood and flesh identity can be saved until the end of the world if they believe the gospel