"First of all", Luke is a mish mash of 2nd hand stories from unnamed source (Luke 1:1-3). Second of all Luke 21:21, it starts out with a quote from Matthew 24:16, which is with regards to the "Great Tribulation", such as the "day of the LORD", which is "behind the door" (Matthew 24:33), and it centers around Judea, the home of Judah/Jews.
Ephraim (the house Israel), went into captivity around 700 BC by way of Assyria, and remains "scattered among the nations". Judah went into captivity much later by means of Babylon, and they have both remained separate (Zechariah11:14).
Judah/Jews, have mostly come out of the nations following the 1st and 2nd world wars, and set up the nation of Israel in Judea. The Jews are still fleeing the North/Europe because of persecution.
As for Ephraim (the house of Israel), being "crushed in judgment" (Hosea 5:11) and Judah being torn to pieces (Hosea 5:14), they have not been together. You might want to throw away your KJV if you think Ephraim and Judah are together at this time. If that were so, they wouldn't have to be reunited on the "land I gave to Jacob" (Ezekiel 37:24-25) under one leader.
As for your quote from Jeremiah 3:18, for when they come together, that will be after the day of the LORD (Joel 2:31-32) when they have "acknowledged your iniquity" (Hosea 5:15), which is after 2 days (2000 years) (Hosea 6:2), when they call "Jerusalem 'the throne of the LORD' " (Jeremiah 3:17)
You don’t like Luke 21:24? That’s fine, a lot of people don’t due to the fact that it makes it undoubtebly clear that the people in Israel are not the biblical Israelites.
Now look at what you just said — you said that the two kingdoms have never been in captivity together... and that is true. Except for right now, they are being oppressed together, like how Jeremiah 50:33 clearly says. Jeremiah 50:33 is obviously not talking about the past because the two kingdoms have never been in captivity together like you just said.
“Thus saith the LORD of hosts; The
children of Israel and the
children of Judah were
oppressed together: and all that took them captives held them fast; they refused to let them go.” [
Jeremiah 50:33]
So according to bible prophecy, both kingdoms would be oppressed/in captivity together until the time comes for them to leave and go back into the holy land. Bible prophecy does not say that Judah will go first, or vice-versa — prophecy says that they are both being oppressed together, and that they will leave the land that they are in together.
“In those days the
house of Judah shall walk
with the house of Israel, and they shall
come together out of the land of the north to the land that I have given for an inheritance unto your fathers.” [Jeremiah 3:18]
The people in Israel have not fulfilled Israelite prophecy, and they also have not fulfilled any of the prophetic curses (Deuteronomy 28:15-68) that the bible says would be on the Israelites as a sign forever (Deuteronomy 28:45-46).
The prophecy in Ezekiel regarding both kingdoms appointing one leader is going to happen after the prophecy in Jeremiah 3:18, once both kingdoms walk together into the holy land. Just like how Hosea 1:11 says. Prophecy does not say that Judah will return to the land first, or anything of the sort. Prophecy says that both kingdoms will leave captivity together > walk into the holy land together > appoint one head.
“Then shall the children of Judah and the children of Israel be gathered together, and appoint themselves one head, and they shall come up out of the land: for great shall be the day of Jezreel.” [Hosea 1:11]
The israeli people are not the biblical jews — they themselves openly admit this in their encyclopedias, almanacs, and even in videos that can be found on the web.
“I know thy works, and tribulation, and poverty, (but thou art rich) and I know the blasphemy of them which say they are Jews, and are not, but are the synagogue of Satan.” [Revelation 2:9]