Alternatively, you can also select the default camera from the Camera settings page:

If you prefer a more technical approach or if the Settings app isn't showing all your devices, use the Device Manager. Windows 11 Default Camera - Microsoft Q&A

If you're still having issues, ensure that your camera is properly connected and installed. If you're using a USB camera, try unplugging and replugging it.

To select the default camera in Windows 11, follow these steps:

Reference: Microsoft Support