IPhone 13 Pro Camera shutter button is unreliable
Camera shutter button when depressed does not always result in a photo! Never been an issue any other iPhone I have owned? Very Frustrating!
iPhone 13 Pro Max, iOS 15
You have to be kind of careful, as getting somewhat to the edge of the shutter button can lead to the camera attempting to take a video, and if you tap it just slightly there, it should take an extremely short video.
You also have the option to use one of the volume buttons to act as the shutter button to take a photo. Try restarting your iPhone and see if that helps.