It is possible to use the BT Smart Hub (aka homehub 6) with your own third party router. However, if you connect the BT Smart Hub straight to your router without changing some of the settings you will most likely encounter issues.
I won’t list the reasons that you would want to use a third party router, for me I wanted to use it in a Dual WAN setup with my Asus RT-AC68U.
There are 4 steps things that need to be done to ensure good compatibility. The steps are as follows: