“Protestants in Ulster are Scots”
Irrelevant. They’re Irish, and THAT was your ‘question.’
The Jewish People were not ‘converted’ by some missionary.
They are the descendants of some six million individuals of the same large, extended family, who heard the same revelation at the same time at the foot of Mt Sinai, who’d agreed to be subject to what they were taught at that time
— and who have re-told its story annually to their children for the past 3400 years.