Radio frequencies

I understand that bluetooth uses a band frequency of around 2.4GHz. Wifi on the other hand will use 2.4GHz to 6GHz. I am wanting to develop an app that can process a higher frequency of radio but have been told that the hardware in devices for wifi, cellular and bluetooth are just not capable for that sort of thing as they are only made to work with certain band frequencies. I would like to ask someone with a deeper understanding of this because I seem to get different answers everywhere I look.