@Sankalp 

No, if you want smart connect enabled you will need to set the A6 in router mode.

@Tony 

Surely this must be a typo?  Are you saying that the Archer A6 V2.0 firmware V 1.17 just purchased new in May 2021 is not only incapable of seeing seeing connected clients in AP mode, but also incapable of serving the same ssid on 2 and 5 ghz?  I thought that feature has been around many years.  The UI is letting me configure it that way without indicating there is a problem, but yet devices that are 3 feet away and CLEARLY 5g capable are being given a 2gh connection.  Is there no workaround for either of these 2 major issues?  Does connecting it to switch via lan port or via wan port make a difference?  Perhaps static ip vs Smart IP(DHCP) for its lan assinment from the main router?  Perhaps some cron job from pfsense to flood it with arp pings or something?  These are not minor firmware bugs, these are well industry standards expected in a device like this for many years. 

Look I'll implement a workaround fine just tell me what to do, but if thats not this thing is going back to the store in a week.