True or False Claims of Kazarian History - Judaism

Arguement for Ashkenazi Jews - Are they the biblical Jews of Palestine? that came from the land of jerusalem? or are they euro caucasian jew from Karazaria in Europe.

if so then why do they persist that PALESTINE / ISRAEL is their homeland?
if they never came from there? and is it true that these peoples: kazarians
became jews, by adopting the jewish religion. Then what were thy before? pagans?