There was Saxons with origin in Saxony living in Kingdom of Hungary
I even seen Saxon church from somewhere in Yugoslavia in this forum posted
The reality a lot of Balkaners could assimilate Saxons in middle age, same with my father family and they did. I have some low Germanic admixture in my DNA 14.4%. 6.4% is show as Saxony Germany, the other 8% Scandinavian (mother side is more likely bulk of Scandinavian)

