iOS: Wi-Fi settings grayed out or dim

Hi guys,

I have the same problem as discussed by others as well. I cannot access Wi-fi, being grayed out, Bluetooth tries on and on to connect and i cannot even stop it. Because of this my battery lasts less than 3h/day.

I did reset the network settings as well as all settings, I restored everything, but it's still not working.

Please advice. Many thanks!

Andra