OK, it seems not possible in router web UI nor the MyJio app BUT BUT BUT in the Jio website if you login to your account and go to the WiFi section of device settings there it has an option to set SSID name and also disable the 2.4 and 5 ghz radios and it shows a message "it will take some time" so I made the change and waiting to see if it actually works and how long it might take