Those who like to denigrate British Israelites and other theories about the whereabouts of the 10 Northern tribes, have never properly researched the facts.
Not sure any human derived historical "facts" can supersede 2 Chronicles, Ezra, and Nehemiah in my perception. And one really doesn't have to denigrate the British Israelite concept. It denigrates itself by avoidance of the evidence in scripture.
Nehemiah 9:1-2 Now on the twenty-fourth day of this month the
children of Israel were assembled with fasting, in sackcloth, and with dust on their heads. 2 Then
those of Israelite lineage separated themselves from all foreigners; and they stood and confessed their sins and the iniquities of their fathers
Nehemiah 11:3-4 These are the heads of the province who dwelt in Jerusalem. (But in the cities of Judah everyone dwelt in his own possession in their cities—
Israelites, priests, Levites, Nethinim, and descendants of Solomon's servants.) 4
Also in Jerusalem dwelt some of the
children of Judah and of the children of Benjamin.
Ezra 10:5 Then Ezra arose, and made the leaders of the priests, the Levites, and
all Israel swear an oath that they would do according to this word. So they swore an oath.
Ezra 9:1 When these things were done, the leaders came to me, saying, “
The people of Israel and the priests and the Levites have not separated themselves from the peoples of the lands, with respect to the abominations of the Canaanites, the Hittites, the Perizzites, the Jebusites, the Ammonites, the Moabites, the Egyptians, and the Amorites.
Ezra 8:35 The children of those who had been carried away captive,
who had come from the captivity, offered burnt offerings to the God of Israel: twelve bulls for
all Israel, ninety-six rams, seventy-seven lambs, and twelve male goats as a sin offering. All this was a burnt offering to the Lord.
Ezra 8:25 and weighed out to them the silver, the gold, and the articles, the offering for the house of our God which the king and his counselors and his princes, and
all Israel who were present, had offered.
And throwing in 2 Chronicles, before the captivity of the northern kingdom and the exile...
2 Chronicles 30:11 Nevertheless some from
Asher, Manasseh, and Zebulun humbled themselves and came to Jerusalem.
2 Chronicles 11:13-14 And from all their territories the
priests and the Levites who were in all Israel took their stand with him. 14 For the Levites left their common-lands and their possessions and came to Judah and Jerusalem, for Jeroboam and his sons had rejected them from serving as priests to the Lord.
2 Chronicles 11:16 And after the Levites left, those from
all the tribes of Israel, such as set their heart to seek the Lord God of Israel, came to Jerusalem to sacrifice to the Lord God of their fathers.
2 Chronicles 15:9 Then he gathered all
Judah and Benjamin, and those who dwelt with them from
Ephraim, Manasseh, and Simeon, for they came over to him in great numbers from Israel when they saw that the Lord his God was with him.
2 Chronicles 34:9 When they came to Hilkiah the high priest, they delivered the money that was brought into the house of God, which the Levites who kept the doors had gathered from the hand of
Manasseh and Ephraim, from all the remnant of Israel, from all Judah and Benjamin, and which they had brought back to Jerusalem.
This is not an exhaustive list of supporting passages, but it does get the idea across that there are no lost tribes that drifted off somewhere. They were all present in the southern kingdom to varying degrees and were known, likewise they were all represented in the different remnant returns from the Babylonian exile.
So then, it becomes a simple choice for me.... follow the imaginings of various human historians with an agenda or the scripture. Seems like an easy choice.
The NT shows 4 tribes known. The 2 Chronicles specifically show 8 named tribes and those not mentioned are covered in "all Israel" statements in those 3 books. And with 8 named as present and accounted for in those passages, it becomes pretty tough to say 10 of the 12 were lost.