My Modem/Router as supplied by my internet provider just has a bank of RJ45s on the back so any wifi router would be on the home network as I believe the modem connections are a hub not a switch.

I can’t use the GL-B1300 as an access point.
I bought it to use as a dedicated VPN access point so my Chromecast could connect to France so I can watch French TV.
The GL-B1300 only supports working as a VPN client when it is in Router mode.