How to change Siri's default search engine(macOS or iOS)?

Apple introduces Siri to macOS, sadly, like iOS, Apple kind of determines your geolocation by your Wi-Fi network even if you turn off location service. This forceful location strategy is really brutal. Siri's default search engine in China, both on macOS and iOS, is Baidu, which is truly rubbish.

I know in iOS it's really hard to change Siri's default engine, since iOS is very closed and "secure". But macOS is a desktop operating system, relatively more customizable. Is there a way to make Siri believe you're not in China, even a difficult way?