Regarding the camera shutter sound, please read the FAQ pages ...
Other camera issues can be worked around by installing the Open Camera app from the Play Store. It has more manual control and works for me ...
The network handover between 2G/3G/4G is up to your mobile operator. Please make sure the phone is fully updated, and answer 'Yes' if the phone requests a reboot to apply carrier settings.
If it still fails, then I suggest you consult the mobile operator and ask for a replacement SIM card, especially if the SIM is old, or if it is cut to size?
They should provide a replacement SIM for free in case of any connectivity issues.