That Wifi and LTE is how BlueLink and UVO connect to the (limited) internet. It is only used for very limited things like turning on your heating, cooling, SOS features etc. It is NOT used to get traffic information of any kind. The Kona displays an LTE symbol in thetop right corner, that is how it connects. It is basically a data-cell-phone connection that can only connect to the Hyundai Server to get very specific information.
You don't have traffic on BlueLink! BlueLink doesn't do traffic!
The traffic that you get on the cars built in map is being received through a hidden data channel that is sent via HDRadio. I don't want to get into explaining how HDRadio works, that is too complicated, but it sends additional data with your normal FM Radio. IF you have only a normal radio, it will only receive the FM Sound that you hear (actually there is some data sent with that too, but again too complicated to explain here). But IF you have a HDRadio compatible radio it will receive that additional data, that can be displayed on your map. It's basically "hidden" in the music!
It's not a random radio signal. The HDRadio scans stations in the background, even if you have turned off the radio. It will still receive that additional data and just take it and display the traffic info on your screen. There is basically nothing you can do about it.
Again, the map system is NOT completely separate and closed. The map data (roads) are ONLY on that SD card and cannot be updated in any other way. However, that doesn't mean, that the traffic info received through the radio cannot be "superimposed" onto that map. Because that's basically what's happening. In fact BlueLink doesn't have anything to do with that!