with new routers and hardware the new routers have two radios on them. and most of them get named the same in the router set up. what i would do if go into the router make sure the 5g radio is on then in the ssid field of the 5g radio put in 5g at the end of the ssid name. save and exit then see if your dongle can see the 5g radio. if it cant make sure you have the newest drivers from the dongle or the chipset vendor that the dongle uses.