Under international law, you become the citizen of the country you’re born in, period.
There is an exception for diplomats and military dependents, who always receive the citizenship of their home country.
Depending on a country’s citizenship rule, some countries may allow dual citizenship.
Huh?
Very few countries allow citizenship only from birth in their country.
My grandson was born in Hong Kong a couple of years ago. There is absolutely no way that he could claim Chinese citizenship since both of his parents were American citizens with no Chinese ancestry.
This is as untrue as untrue can be. There is NO 'international law' on the subject. Each and every nation decides for itself who it does and does not consder its citizens. And most do not recognize naked jus soli citizenship. Period.
There is no International Law as you claim there is.
Interestingly, only 30 out of 196 countries grant citizenship upon birth.