Quick Summary of British Israelist Thinkin

It would seem that having a King in ones ancestry would be proof that one is a Jew. Wasn’t the scepter supposed to be in the hands of Judah? Weren’t the Kings to arise from the womb of Sarah? This makes me a British Israelist. The monarchy didn’t intermarry, or was um inbred. 2,000 years and no messiah. I can hardly believe that, especially that there are 4 ancestries through different countries the monarchy and Presidents have that go back to Judah. And, how did this Judeo-USA government come about, but through people that trance their ancestry to medieval Kings.