On your R6080, login on routerlogin.net , head to Basic -> Wireless ... here you can set the wireless network name (SSID) for the 2.4 GHz and the 5 GHz band individually. Ensure the 5 GHz is set to a different name than the 2.4 GHz, when connect your mobile with the config app or whatever to that 2.4 GHz WLAN name. Now the discovery and configuration should be workable.
Head to the vendors and developers which don't understand L2 networking, and are making over-"s***d" Apps. Broadcast, Multicast, whatever they use for the discovery - most Netgear consumer routers (I admit probably not 100%) are nicely forwarding this traffic between the different radios. And don't worry, they won't use other "low level" stuff because (not only) iOS won't allow that kind of low-level interface access.
Look, even Netgear's Switch Discovery L2 protocol 8899 (to be correct originated from RealTek) does distribute nicely - just as one of the many "legacy" chip set maker L2 protocols.
I take it you're talking about the R6080 thats listed under your description? here's the link to the support page for the R6080, this includes the manual. Its got the directions on disabling the 5ghz radio.