Incorrect DNS configuration?

I recently got T-Mobile home internet.  The gateway device is a Sagemcom FAST5688W.  When attaching devices to Wifi, sometimes my devices are getting delayed connectivity to the Internet.  After investigating the network configuration being provided to the WiFi device from the gateway, I noticed what appear to be DNS servers that aren't responding to queries.

Here is an example device network configuation:

And here is testing of the DNS servers.  The last one is an IPv6 test I believe of the 5688W:

$ nslookup
> server 192.168.12.1
Default server: 192.168.12.1
Address: 192.168.12.1#53
> www.t-mobile.com
Server:         192.168.12.1
Address:        192.168.12.1#53

Non-authoritative answer:
www.t-mobile.com        canonical name = www.t-mobile.com.edgekey.net.
www.t-mobile.com.edgekey.net    canonical name = e71824.dsca.akamaiedge.net.
Name:   e71824.dsca.akamaiedge.net
Address: 23.45.123.55
Name:   e71824.dsca.akamaiedge.net
Address: 23.45.123.74
Name:   e71824.dsca.akamaiedge.net
Address: 2600:1405:7400:28::17c2:7f92
Name:   e71824.dsca.akamaiedge.net
Address: 2600:1405:7400:28::17c2:7f8f
>
>
>
> server fd00:976a::9
Default server: fd00:976a::9
Address: fd00:976a::9#53
> www.t-mobile.com
;; connection timed out; no servers could be reached

> server fd00:976a::10
Default server: fd00:976a::10
Address: fd00:976a::10#53
> www.t-mobile.com
;; connection timed out; no servers could be reached

>
>
>
> server fd8a:ee5b:e6fb::1
Default server: fd8a:ee5b:e6fb::1
Address: fd8a:ee5b:e6fb::1#53
> www.t-mobile.com
Server:         fd8a:ee5b:e6fb::1
Address:        fd8a:ee5b:e6fb::1#53

Non-authoritative answer:
www.t-mobile.com        canonical name = www.t-mobile.com.edgekey.net.
www.t-mobile.com.edgekey.net    canonical name = e71824.dsca.akamaiedge.net.
Name:   e71824.dsca.akamaiedge.net
Address: 23.194.127.146
Name:   e71824.dsca.akamaiedge.net
Address: 23.194.127.143
Name:   e71824.dsca.akamaiedge.net
Address: 2600:1405:7400:28::17c2:7f8f
Name:   e71824.dsca.akamaiedge.net
Address: 2600:1405:7400:28::17c2:7f92
> exit

~ $