Why is my camera on my iPhone 7 Plus delayed ?

Going to try to best to explain - As of recently, my camera on my phone has been acting up. When I click the camera button the app opens up however the screen remains black and I can’t capture a photo. This same scenario occurs when I open Snapchat and try to take a picture or Instagram photo. After several times closing the app up and waiting it finally works randomly. I tried resetting my phone and still isn’t fixing the issue. Has anyone experienced this ? What should I do from here ?