Mute button not muting the camera shutter sound

My iPhone 12 pro max, even if I use the mute button on the side of the device, ON to mute, camera still make very big shutter sound.

Only with live mode on, it is silent. the moment I switched to portrait mode, again the shutter sounds comes on. this is even the mute still ON.

When I use camera through WhatsApp also, it makes the same big shutter sound.

How can I mute my camera shutter sound?