I do know what I am doing and talking about. Not to be “that guy” but I have a technical degree in computer networking from years ago. May not remember how to configure a cisco enterprise switch from command line anymore but I would still say I am advanced.
This is from the router, might be able to get something more definitive from command line. I have never had this be wrong. The Wireless “log” breaks it down between which SSID and radio the devices are on and this hub is clearly on the 5GHZ
Wireless Log (headers in separate shot because its a huge list)
Searching around for the specs it is hard to find anything other than the page you gave a screenshot from. I did find this on the forums.
I do have a 5Ghz only SSID as well, I could test connecting to that later today just for fun.
Also cannot find any useful info about the Wifi in the ST Advanced web UI. Only the SSID is listed and no other details.