I assume that you are looking to segment your network with VLANS (i.e. 1 for smart devices, 1 for computers, 1 for guests etc) which the smart hubs cannot do.
If this is the reason then grab an Openreach MT992 modem (if you are on g.fast) off eBay and use your own router with a managed switch and seperate AP's to created your VLANS as needed
If you are looking at giving a seperate wifi ap for certain people/things but dont mind the traffic being mixed then grab an access point, plug it into one of the lan ports on the hub and setup a new wifi network name and password.
you will then have 2 wifi networks but traffic will be mixed and each device can communicate with others on the network
