The sanitized DB endpoint should also wipe the birthdate field (see https://github.com/kiwi515/ogws/blob/master/include/RVLFaceLib/RFLi_Types.h#L252).
A database migration should be written to sanitize existing Miis, only leaving the sysID field. Then the normal DB fetch should also wipe everything but sysID.
The sanitized DB endpoint should also wipe the birthdate field (see https://github.com/kiwi515/ogws/blob/master/include/RVLFaceLib/RFLi_Types.h#L252).
A database migration should be written to sanitize existing Miis, only leaving the sysID field. Then the normal DB fetch should also wipe everything but sysID.