It's a Taiwanese last name. But then you can say that it's Chinese too. It's complicated. The majority of Taiwanese people's ancestors are Chinese, hence they carry Chinese surnames. The reason why Kuo is only seen on Taiwanese people is because only Taiwan spells it that way.
Ethnicity of surname amyx
It could be any ethnicity, actually.
Arpaio can be a Gentile or Jewish surname
Chinese
Turkish
jewish
daleb
Austrian
Dutch
German
irish
Egyptian