Disappointed with C7000v2 and EX8000 combo - "one wifi" mesh setup does not work

OS: WIN10 Pro
MODEM/ROUTER: C7000v2 AC1900-Nighthawk X4 Dual Band Cable Modem Router
EXTENDER: EX8000 Nighthawk X6S Tri-Band WiFi Mesh Extender

Recently purchased C7000v2 and was hoping to use the "one Wi-Fi" feature on the EX8000 as well as the "smart search" frequency selection. My initial set up is listed below and was basically using a single Wi-Fi name for the system:

Unfortunately, this did not work as the extender was not able to get provisioned sufficiently to get to the Internet through the router. (Note that all passcodes were the same regardless of SSID)
My next set up was to try and use the "one Wi-Fi" feature on a per frequency basis where the 2.4 GHz band had one name and the 5 GHz band had another:

Again, the same issues between the router and extender - ultimately devices connecting to the router wifi got to the internet, but thoses that connected to the extender did not.

Finally, I had to resort to separate SS ID names for each device and frequency, with the table below.

I realize the difference between the dual band router and the tri-band extender, but I was hoping to get something that was at least an improvement over 4 separate Wi-Fi names. The router is set up on Comcast and basically has default settings including DHCP. Prior to this I was using a Motorola SBG 6580 cable modem with a dedicated 5G link to the extender. I did not try the "one Wi-Fi" under this configuration but was using the last (4 name) network.  Was hoping that having a Nighthawk router and Extender would allow better setup.

KT