How do you override the host's IPv6 DNS providers?

[RNHurt]

I experimenting with NextDNS as my upstream DNS provider.  So far I like it quite well but I'm having a bit of trouble getting DNS configured.  I was able to set my IPv4 DNS providers in the Services --> DHCPv4 --> [LAN] config but I can't find where to set the IPv6 DNS providers.  The IPv6 Services --> DHCPv6 menu only has "Relay" & "Leases" and neither of those offer DNS configs.

Where can you override the host's IPv6 DNS providers?  Do I need to install a NextDNS plugin or something?

[WN1X]

I simply added the DNS servers I wanted under System: Settings: General, setting the correct interface (WAN_DHCP/WAN_DHCP6) depending on the address entered (IPv4/6).