I have been thinking about this a lot. Our wording.
Like how do we differentiation between an US-American and a Canadian-American and a person born of one Candain parent and one US-American?
Well I have been thinking, here are my ideas.
For an American from the US we could use: Union-American, Washington-American, Washingtonian, or simply call them by their state demonyms(https://en.wikipedia.org/wiki/List_of_demonyms_for_U.S._states_and_territories)
For an American from Canada, we could use: Canadain(duh), Confederal-America, Macdonnal-America, Mac-American or by their provinces demonym: https://en.wikipedia.org/wiki/List_of_adjectival_and_demonymic_forms_of_place_names#Canadian_provinces_and_territories
I myself prefer to use local demonym, but when needed I think we should use Union-American and Canadian myself. I hope this works! Thanks for reading, don’t hurt yourself, God bless!