why no windows app for managing our gateway

I am at work.   I can VPN into my home network with my Fortinet Firewall IPSec VPN.   My phone can't see my Gateway from XFinity because it is not in the VPN.    Whose stupid idea was to tie the Gateway management into the WIFI and not an internal subnet?   The app on my phone shows no devices because it isn't at home.   WIFI Intelligence isn't very intelligent.  WIFI isn't very safe for management of devices.   People can hack your Wifi.  I would keep it disabled.   I want the gateway in IP passthrough mode with all security disabled.  The Fortinet handles all security.

My home WIFI is on my Fortinet Wireless Access Points.   I treat my AT&T Gateway as a IP Passthrough device so my Fortinet Firewall gets the IPv4 and IPv6 information.  Fortinet is the top tier of firewalls and security devices.    I can't access http://10.0.0.1.  I get a stupid message to use the phone app.   I am at work.   I can't access the device.   I went with your modem for better performance.   It is a secondary connection that my children use.  My wife uses the AT&T Gigabit Fiber for work.  It is full gigabit fiber to the modem.  Gig Up/Gig Down 2 ms latency.   Any way to change the modem to allow http://10.0.0.1 to work?