I understand the point being explained here, but is this really accurate? I don't know of any SDR platform, let alone a "dongle" with anywhere near the capacity necessary to operate as a wifi AP.
Maybe some radio smartperson can clarify?
(802.11ac is out of bounds, its channels are 80MHz minimum.)
it's been possible to operate a variety of wifi cards in host AP mode for like 10 years or more. have a search and you'll see this is easily doable.