The distinction between the Jews and the Israelites was eliminated at the end of the seventy year captivity and all Israelites have been called Jews ever since. The post exile prophet Malachi did not address just the tribe of Judah, but all of Israel which means all twelve tribes. Did he commit a gross misunderstanding?
Jesus said that He had come to save the lost sheep of Israel, which means all twelve tribes. Was He mistaken in His understanding about the people He came to were? Whenever the Apostles addressed the people of Israel whether in preaching or writing, were they mistaken about who they all were?
And we are called "Israel" in Romans chapter 9 in the figurative and spiritual sense, but that title is not often applied to the Church in scripture which maintains a distinction between the Church, which transcends all nations, and the nation of Israel which was established through a bloodline and whose territory and borders were defined.
Your idea that there is now no distinction between Jews and Israel, cannot be correct as this means that Ezekiel 37 happened after the Babylonian captivity. Simply not credible!
Only a few thousand Jews came back to Jerusalem then, neither then or now are those people a vast multitude, as Israel was prophesied to become.
The Jews have usurped the name of Israel, in fact it was the American administration of 1948, that insisted they call the new Jewish nation; Israel. David ben Gurion was about to declare it the nation of Judah, as it is the Jewish homeland.
I don't deny that the Jews are also Israelites, but the main group of Israelites; the Northern ten tribes, remain scattered among the nations, awaiting their redemption and restoration.
Note that the exile punishment of Israel and Judah was for a decreed time. Ezekiel 4:4-6 Judah has returned, but Israel not yet.
The point is; the whole of the prophesies, OT and NT, apply to ALL the Israelites and to say they are fulfilled in only Judah, is quite wrong and a contradiction of scripture.
It is we Christian followers of Jesus, who are the inheritors of God's Promises to all Israel, we are the Overcomers for God, His Victorious ones and all of the Promised Land will be our possession. Isaiah 62:1-5 John sees us there in Revelation 7:9. BEFORE Jesus Returns.