le_gnss_Enable/le_gnss_Disable are API to set/unset the GNSS feature . by default it is set, but if in an use case, the GNSS is not at all required , the feature can be disabled thanks to that API.
le_gnss_Stop is used to stop a GNSS session , usually started with le_gnss_Start.
so it will end an acquisition session or a tracking area session.