It’s exactly true. God knows all, and this is His creation and tapestry. He didn’t send Jonah to Nineveh by accident, He knew that later the Gospel would be preached to the entire world, before the apostles understood that and before the New Testament was written.
That being the case, all matters must be established by two or three witnesses. Jonah, going to Nineveh was the first witness of the grafting on of the non believing heathen/gentile to the Olive Tree.
Peter then receives a vision on the rooftop to bring the good news to gentiles in Acts 10, which is the second witness of this plan. None of it involving a new gospel. Because we know in Hebrews 11 it was by faith that Abel, Enoch, Abraham etc pleased God. None of which had the law.
Acts 11:17-18 (AMP) 17 “So, if God gave Gentiles the same gift [equally] as He gave us after we accepted and believed and trusted in the Lord Jesus Christ [as Savior], who was I to interfere or stand in God’s way?” 18 When they heard this, they quieted down and glorified and praised God, saying, “Then God has also granted to the Gentiles repentance that leads to eternal life [that is, real life after earthly death].”
Jesus even calls Peter, the son of Jonah:
Matthew 16:17 (AMP)
Then Jesus answered him, “Blessed [happy, spiritually secure, favored by God] are you, Simon son of Jonah, because flesh and blood (mortal man) did not reveal this to you, but My Father who is in heaven.
this is further connection and witness of Gods plan and refutation of any and all gnostic and heretical views/doctrine that Paul was off doing his own thing. Understand?
So when Paul has his revelation (a revelation is not a new gospel, you’re being disingenuous by saying so) of bringing the good news to the gentile/heathens, which was discussed in council in Jerusalem, just as it says in Acts, and further it is witnessed (ie, attested to as authentic) by both Jonah going to Nineveh, who we are told will stand in Judgement in both Matt 12:41 and Luke 11:32 and Peter’s vision Acts 10, thereby establishing the matter as Gods will and not some crackpot scheme by Paul.
Luke 11:32 (AMP)
“The men of Nineveh will stand up [as witnesses] at the judgment with this generation and condemn it, because they repented at the preaching of Jonah, and look, something greater than Jonah is here.
further more, the word gentile is used incorrectly by many. The old definition was: A pagan or heathen, ie non believer. Because we know that those who believe on Jesus Christ are grafted in and become as one of the same olive tree. There is no distinction in believers in Jesus Christ. You are either a believer or not.