No, there's no way to use the camera to unlock your iPhone without passcode or FaceID. When your iOS device is locked, you can access the stock Camera app from Control Center to only capture photos and videos. Also, you'll be able to see only those photos & videos that you've recently captured with the locked iPhone. On iOS 9 or older versions, there was a glitch that allowed you to unlock iPhone using camera. Today, nothing like that is possible.