If you have plugged in the router from the day you got it and not changed anything on it manually, like your wifi password or any other settings then a factory reset just puts it back to the way is from the day you plugged it in. The only thing you need is the admin password on the bottom of the router to access the router and change the password to something of your own choosing should you wish to enter the router menu. All your devices will automatically connect again to the network as long as you never changed the network key or SSID in the router settings.
***********************************************************************************************************************************
Super Hub 4.0 (modem mode) - Gig1 Fibre FTTP - Asus RT-AX82U & Asus RT-AX56U with AiMesh setup
***********************************************************************************************************************************