This topic is contentious for at least three reasons.
1. Many modern Jews believe they are still the chosen spiritual source of God’s wisdom and holiness as the ‘superior’ people on earth.
2., Many Christians believe that these modern Jews since Christ are the actual physical and even the spiritual descendants of Israel or at least from the house of Judah. They have built some of their spiritual doctrine of prophecy (for example, dispensationalism) based on it. And they won't give it up without a fight.
And 3., Christ united all physical tribes, including Israel, all nations, under one Spirit and one Body for the Father. And he is its lord Christ who did not replace Israel of the Law; he incorporated them into the covenant of grace with the new Israel of today.
This is true Israel we have today, in the hearts of a believer, from any origin, culture or nationality. Life blood does not count anymore, only the spiritual blood of life given by the Father and Son. And then these modern Jews were DNA tested and flunked 'the test'..more on this later.
---some fragmented notes will be added to this thread that will follow this OP----------
You've gone too far, actually leaving Bible Scripture, with the confusion of no.2, and especially with no.3.
1. Modern Jews (not ten tribes) of course still believe they are a chosen seed by God. And it's true, but it does not mean they are superior. They were 'chosen' for a duty involving The Gospel of Jesus Christ. They were to be caretakers of The Gospel to the nations. That's about a responsibility to all other peoples, and not about making Israelites superior to the nations.
Now the Jews who think God chose Israel to mean they are superior, the Jews that think that are simply listening to the false crept in unawares of the "synagogue of Satan", those who say they are Jews, but are not.
They are being duped by Satan's host that has crept in among them and which are not seed-born Israelites. God having place the 'spirit of slumber' upon the Jews is another reason why those liars of the synagogue of Satan is able to deceive them. But Paul in Romans 11 showed God will remove their 'blindness' when the fullness of the Gentiles comes in.
2. Most Churches wrongly teach that ALL of the seed of Israel are JEWS, which Biblically and historically, is NOT true.
The title of Jew, per the Jewish historian Josephus (100 A.D.), originated with the three-tribe southern "kingdom of Judah". God split old Israel into 2 separate kingdoms in Solomon's day, because Solomon had allowed his many foreign wives to bring their idol worship in among Israel, and Solomon participated (see 1 Kings 11 forward). So God setup Jeroboam of the northern tribe of Ephraim over the northern ten tribes, which became the "kingdom of Israel" with its capital city at Samaria in the north. Jeroboam fell away too, and politically setup 2 gold calf idols among the ten northern tribes to prevent them from going to Jerusalem to worship. A small remnant of the ten northern tribes refused the idols, and went south and joined with Judah, also becoming Jews. The Levites in the north also left and joined with Judah in the southern kingdom. This is still... how it is today, except the ten northern tribes are LOST.
The reality still today per God's Word is:
a. the Jews only make up about 1/3 of total number of Israelites.
b. the ten Lost tribes make up the Majority of Israelites, but most of them still don't know it.
3. Not all Israelites of the 'seed' have been united in Christ Jesus yet today. The majority of the Jews of the 3-tribe "house of Judah" are still blinded by the spiritual stupor God put upon them, per Paul in Romans 11.
And the idea of the literal 'seed' of Israel does still matter, for even as Apostle Paul said in Romans 11:2 that God has not cast away His which He foreknew. And per Romans 11:29 "For the gifts and calling of God are without repentance." That means God will not take back what He promised the seed of Israel. This is why the Old Testament prophets show God's declaring the future restoration of all 12 tribes back to the holy land of promise, with David as their prince, and Lord Jesus as KING of Israel. This is also why Apostle Paul used the term "commonwealth of Israel" in Ephesians 2 about Gentile believers, because it means God's future Kingdom of Israel will be a 'commonwealth' of nations, but the 12 tribes will still be a specific Israel nations restored in the holy lands. Even Isaiah 19 reveals that Israel, Assyria, and Egypt will each be one third in God's future Kingdom on earth.