Why did you feel the need to specify that the USA are a representative democracy? A lot of other countries on your list are, I think this it is far more common then direct democracy.
It was added by the AI; "[ChatGPT] originally included that extra phrase only because many English-language sources habitually describe the U.S. as a “representative democratic republic”. To keep the wording consistent, you could simply shorten it to “Federal presidential republic”."
I thought we were discussing definitions from a professional source, where every word was carefully weighted for its inclusion and meaning, instead of "the common man".