Interesting. There are some apps that open with a splash screen and generate a sound however the Settings app is not one of them. The Settings app opens quietly and shuts down quietly. You stated that you heard helicopter sound affects and radio station tuning effects. Does that happen every time you open the Settings app? It probably does not and if it doesn't then the sounds are coming from something else and perhaps from an app running in the background.
Try and Force Restart your iPhone EXACTLY as shown below and see whether that resolves the issue:
- Press and quickly release Volume UP button
- Press and quickly release Volume DOWN button
- Press and Hold the SIDE button until an Apple logo appears and then release the Side button (Can take up to 20 seconds. (DO NOT release Side Button when invited to Slide Power OFF).
Axel F.