You also explicitly enable and train FaceID on an iPhone, yet Apple does not collect or store any biometric data anywhere but on your phone. The issue here is

You also explicitly enable and train FaceID on an iPhone, yet Apple does not collect or store any biometric data anywhere but on your phone. The issue here is the collection, storage, and potential use of the data by Google. Google should allow you to opt-in to them collecting that data anywhere off-device, but for now they do not.