Who are the real Jews? Jesus said forsake genealogy and that it doesn’t matter. Lineage only mattered until Christ was born.
Who is the true Jew? Those who live by faith are the children of Abraham - The Children of the Promise.
What is the essence of being a true Israelite? It is not literal descent from Abraham, but faith in God. It's in the Bible: "Know ye therefore that they which are of faith, the same are the children of Abraham." Galatians 3:7. "For they are not all Israel which are of Israel; neither because they are the seed of Abraham are they all children… but the children of promise are counted for the seed." Romans 9:6-8.
The children of promise are those who put their faith in Jesus. It's in the Bible: "And if you are Christ's, then you are Abraham's seed and heirs according to the promise" Galatians 3:29.
Whether they are Jewish or Gentile, God regards only those who have renewed hearts as true Israelites. It's in the Bible. "For he is not a Jew which is one outwardly, nor is that circumcision which is outward in the flesh; but he is a Jew which is one inwardly, and circumcision is that of the heart, in the Spirit, and not in the letter' whose praise is not from men but from God." Romans 2:28,29, NKJV. "For we are the circumcision, who worship God in the Spirit, rejoice in Christ Jesus, and have no confidence in the flesh." Philippians 3:3, NKJV