Hi, my router have wifi N and AC (2.4Ghz/5Ghz) but in dietpi-config scan option only is visible the SSID of 2.4Ghz using my raspberry pi 3 inboard wifi.
In my laptop with Zorin OS 5Ghz SSID is visible and connected.
P.S: I have a SSID to 2.4 band and other SSID to 5 band.
Thanks.