This bulletin outlines the KDS Battery Diagnosis function and diagnosis procedures. The Battery Diagnosis is an on-vehicle battery diagnosis system, utilizing the battery sensor data. The battery sensor which is located next to the battery negative (-) terminal, continuously stores, and saves various data shown below for the last 30 days, including the key off position.
This is just an informational TSB but does apply for diagnosing issues with the EV6 12V battery. It should be able to determine if the 12V battery is holding a charge and if there's a drain while the car is off.