Questions about example sentences with, and the definition and usage of "Puppeteer"

A: It should be "I'm not a puppeteer."

There is a very slight difference in nuance.

"I'm not a puppeteer" means that I don't know how to do it. Perhaps I could learn.

"I'm no puppeteer" also means that I don't know how to do it, but there is an additional nuance that I really couldn't do it, even if I tried.

A: There is no difference in meaning. In terms of usage, "puppeteer" is more likely to be used literally, while "puppet master" figuratively. Although it isn't a strict requirement.