And if some of the branches were broken off, and you (Gentiles), being a wild olive tree, were grafted in among them, and with them became a partaker of the root and fatness of the olive tree, do not boast against the branches. But if you do boast, remember that you do not support the root, but the root supports you. Rom 11:17, 18

Question: Is the Church separate from Israel? Or has the Church, God’s elect, chosen ones, congregation, assembly, and one flock always been Israel that He graciously engrafted Gentiles into?

You will say then, Branches were broken off that I might be grafted in. Well said. Because of unbelief they were broken off, and you stand by faith. Do not be haughty, but fear. For if God did not spare the natural branches, He may not spare you either. Therefore consider the goodness and severity of God: on those who fell, severity; but toward you, goodness, if you continue in His goodness. otherwise you also will be cut off. Rom 11:19-22

Question: Has the engrafted Gentiles replaced ethnic Israel? Can we, as Gentile branches, be broken off once engrafted? And if so, why?

And they also, if they do not continue in unbelief, will be grafted in, for God is able to graft them in again. For if you were cut out of the olive tree which is wild by nature, and were grafted contrary to nature into a cultivated olive tree, how much more will these, who are natural branches, be grafted into their own olive tree? For I do not desire, brethren, that you should be ignorant of this mystery, lest you should be wise in your own opinion, that blindness in part has happened to Israel until the fullness of the Gentiles has come in. And so all Israel will be saved, as it is written: The Deliverer will come out of Zion, and He will turn away ungodliness from Jacob; for this is My covenant with them, when I take away their sins. Rom 11:23-26

Question: Have the engrafted Gentiles replaced ethnic Israel yet? Does Paul say, or even insinuate, that the engrafted Gentiles will have a different fate than the Israel they’ve been engrafted into?

The fact of the matter is that Jesus is the Root of the Olive Tree Israel, His ONE True Bride! The Scriptures do not reveal a different purpose, nor fate in the end-times for Messiah's singular Bride of Jews and Gentiles. The Gentile Church is not a separate entity. We are not raptured or resurrected separately from the Israel of God. When Jesus comes for His One Singular Bride, we will have the same fate as Israel! When Paul describes the final redemption of Israel by “their acceptance (of Messiah) ” as life from the dead,  he is making an inference to the resurrection!