ipv6 not obtained MG8702 router

I see a few posts on here with no resolution.  I have a Motorola MG8702 router/modem combo.  Firmware version: 8702-19.3.13

IPV6 is enabled, but the DNS servers are blank in the router config.

IPV4 is also enabled, but shows the 2 Xfinity/Comcast DNS servers.

Why am I not receiving the IPv6?  I'm having trouble connecting to resources, which points to DNS.  When that devices connects to something with IPv6, it seems to work fine. 

Should I manually add all DNS servers and use Google's? 

When I run a test, I get a 4/20 and says IPv6 is not supported.  https://ipv6-test.com/

Please help.