@ImHere let's just say that the commonality between Ashkenazi Jews and Yemenite Jews is only 10% and that amount comes from the southern levantine/samaritan like source in both groups. Should both of these groups be considered the same ethnicity as they are now? 10% is just a single water molecule in the ocean. It isn't sensible to claim that just because 2 ethnicities have the ancestry from the same region/same population source that only makes up 10% of one of the group's ancestry enough for them to be considered under the same ethnic lable
Having certain amount ancestry and identifying are 2 different things.
Neither can claim to be "pure jews", but if people didnt randomly converted to judaism, and jews had the same social structure like pashtuns, then yes, both can be considered jews.
You have to look past genetics, and look at culture + family tree/heritage. Some ethnicities are just like that. Father's identity matters the most. And if his son consider himself the same thing(lets say pashtun) as his father, while father is "pashtun" from his father's side, then so is the son. And same can be said for his future descendants
THough i will say, im not arguing for jews now, since people could randomly convert to judaism, and even today. Rather just arguing for this concept: Father's heritage matters most, and you can identify as ethnicity "ZX", no matter the amount of admix from "ZX"