I have successfully used stadia on PC, but when trying to get it set up on my iPhone, after following all the setup steps and ensuring it was up to date and everything, I cannot seem to get stadia itself to recognize that I have an Xbox controller connected to my bluetooth. It is clearly there in my settings, and stadia itself is cleared to have access to my Bluetooth devices, it just doesn’t seem to realize I have one set up.
Same issue here. On the hunt for solutions. Did this ever get rectified for you?