The KJV reads: Matthew 24:14 “And this gospel of the kingdom shall be preached in all the world for a witness unto all nations; and then shall the end come.”

Now too many have read this verse and thought this meant every place in the world (kosmos) would hear the Gospel, including Peru and Australia) before “the end would come.”
BUT the word translated “world” is οἰκουμένη, translit. oikouménē, which means the inhabited land. In the New Testament οἰκουμένη always refers to the Roman Empire. Josephus made it clear that οἰκουμένη meant the four borders of the Roman Empire.

When we understand this, then we understand Matthew 24:14 correctly.
The Apostle Paul in Colossians 1:5-6 “For the hope which is laid up for you in heaven, whereof ye heard before in the word of the truth of the gospel; Which is come unto you, as it is in ALL THE WORLD; and bringeth forth fruit, as it doth also in you, since the day ye heard of it, and knew the grace of God in truth:”

Romans 10:16-18 “But they have not all obeyed the gospel. For Esaias saith, Lord, who hath believed our report? So then faith cometh by hearing, and hearing by the word of God. But I say, Have they not heard? Yes verily, their sound went into all the earth, and their words unto the ENDS OF THE WORLD.“

Romans 16:25-26 “Now to him that is of power to stablish you according to my gospel, and the preaching of Jesus Christ, according to the revelation of the mystery, which was kept secret since the world began, But now is made manifest, and by the scriptures of the prophets, according to the commandment of the everlasting God, made MADE KNOWN TO ALL NATIONS for the obedience of faith:”

Yes, in the first century, the gospel had been preached “in all the world, to all the nations.” So then we should expect that the end came in the first century.
AND IT DID! Jesus was speaking of the end of the temple and the end of the Old Covenant, both of which ended in 70 AD with the destruction of the temple and Jerusalem.