Isolated Wifi with Multiple SSIDs

This is with regards to

Isolated Guest Wifi with Multiple SSIDs


(which is linked in the forum topic mentioned.
This guide is several years old though.

I try to setup a similar configuration. One TP-Link Archer C7 v2 to a fibre modem. I would like to have multiple SSIDs and a network separation between them. That guide on Medium seemed like a good option, but after having it set-up, I do not get a IPv4 address lease.

The other thing, that I find odd is that there is no device in their /etc/config/network

config 'interface' 'public'
        option 'proto' 'static'
        option 'ipaddr' ''
        option 'netmask' ''

Has something changed since that guide was written? Any other considerations?