Settings -> Spotlight -> Turn off everything you don't want. The first few times you open it it even tells you this.
Admittedly I haven't confirmed that this results in no API calls in the latest few macOS releases but it definitely used to stop them, at least a few years ago.
Admittedly I haven't confirmed that this results in no API calls in the latest few macOS releases but it definitely used to stop them, at least a few years ago.