My Chromecast Ultra would not start until I began answering 8.8.8.8
I don't disagree that this is a Bad Thing.I like to use a BSD based router and a PF firewall. My solution:    match in on $i inet proto udp from any to !($i) port {53 123} rdr-to ($i)

"Any UDP packet destined for port 53 (DNS) or 123 (NTP) that is not the gateway ("$i"), redirect them to gateway ("$i").The gateway has daemons listening and caching requests for performance. The client has no idea this is happening.It works great for me.