How can one disable iPhone biometrics with Siri (now that the old way doesn't work)?

Hi all,

Until recently there's been a well-documented way to disable FaceID for iPhones on the next login attempt by simply asking "Hey Siri, whose phone is this?" For some reason this command locked the device and required the passcode fallback on the next sign-in attempt. This is the equivalent of holding the power button down for five seconds or initiating an emergency SOS attempt, but with the convenience of voice control.

I was always suspicious of this method being a workaround that would disappear one day, and as of iOS 18 (I think) this method no longer works.

After some investigation I can't seem to find another command that works, or a reason why Apple would disable this clear security advantage. Does anyone have any insights as to why this change was made and/or a new hands-free way to accomplish this task?

Thank you!