Hello Almara, thank for posting.
This question has been asked in the past in a different thread. However, I just noticed that relying on the command you used or “netsh wlan show interfaces” can be misleading. Let me explain my point: those commands depend on the settings used in the wireless adapter properties window; for example, my dual band wireless adapter is right now forced to connect at 5 GHz and the commands are only giving me 802.11a, this is because the wireless mode was set to strictly use 802.11a.
I recommend you to take a look into the Wireless Mode drop down menu in the Advanced tab. The articles below show the steps for you to get into this window. If the adapter does not show 802.11a as an option, it does not support 802.11ac and will be only single band.