Turn off the camera shutter sound on iPhone SE running iOS 12.1.4
You found one of the methods, Live Photo.

The other is simply to turn the ringer sound down to zero.

Source - Lifewire - How to Turn off the Camera Sound on iPhone

I think the limitation on the ringer mute no longer working is because of recent legislation. No longer is 'upskirting' merely deeply offensive, it is now actually illegal.
That there is still a workaround is possibly an oversight &amp; may be fixed in future.