Not real descendants of Judah, possibly not descendents of Jacob/Israel at all.

9 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 https://www.churchofjesuschrist.org/study/scriptures/nt/rev/2?id=p9&lang=eng#p9 & 9 Behold, I will make them of the synagogue of Satan, which say they are Jews, and are not, but do lie; behold, I will make them to come and worship before thy feet, and to know that I have loved thee Revelation 3:9 https://www.churchofjesuschrist.org/study/scriptures/nt/rev/3?id=p9&lang=eng#p9

I have a few friends who claim Jewish ancestry. One who has shown me their genelogical line back to Judah. Maybe it was faked, though they are full on MAGA & they have told me they are a black sheep in their family because they have embraced Jesus as their Savior. Though they still are accepted in the greater Jewish community locally here because they are a descendant. I still need to take them up on the invitation to go learn directly from some of the local leaders about their specific beliefs. Maybe I will do that at some point.

Ultimately I think you are correct regarding the Khazarians, though I still don't know enough to say those are certainly the ones mentioned in the Bible.

That said, I wouldn't be surprised if all the dual citizens in congress fit these scriptures perfectly.