Technically Johannes Jonkers was not simply a no-maj born wizard. There is a reason to why JK Rowling might have used both No-Maj and Muggle, even though they mean the same thing synonymously. What was written was that he had a No-Maj father and Muggle-born,so Johannes had an American father, who went to Europe (for whatever reason), and met a woman and Johannes was born there (muggle/UK born). He then went to the United States to become a wandmaker.
However, this does not mean, or indicate, if he went to Hogwarts and moved to America or he was young and went to America (where his father was) and became a student at Ilvermorny.
If he went to Hogwarts and became a wandmaker in the United States then he would be British who wanted to know American wandmaking. If he went to Ilvermorny at a young age... he is American. But he could be American wandmaker simply based on the fact he was a wandmaker in America. —