Meanwhile there is no specific demonym for people from the united states, you can say american buy that would also include every other north and south american country
Literally nobody who isn't a Latin American with a chip on their shoulder has a problem distinguishing Americans from "people who live on either north or south america"
Nobody calls Mexicans or Canadians Americans. Nobody calls Brazilians or Peruvians Americans. They maybe North Americans and South Americans but American means someone from the United States. The Canadians and Mexicans I know would be offended if I called them American.
People outside the US all assume "American" means US. Nobody thinks there's even a small chance you are referring to anything else. If you want to refer to South Americans you say "South Americans"