Navigation buttons missed in my iPhone 6s

Has to be something revolving around shared location. Check your privacy and scroll through the list and see wich apps are accessing your location. Turn each one off and turn off location then restart the phone. If need be, delete the app and reinstall the maps app. If it's home control, then you need to check accessibility shortcuts and see what all is on and limit what's on your home control, like camera and add low power mode and turn it on through the process.