I had same problem. WiFi and Bluetooth wouldn't turn on.
I tried many things.
Try first *#0011# then choose WiFi in setting menu and turn off safe mode.
This didn't worked for me.
I went to Samsung service and they changed phone's mother board.
So your problem be ass well a hardware issue.
My WiFi problem solved after service but not it is very weak. Cant connect to WiFi from next room.
Going back to Samsung service today