Multiple IPs for DNS Server

[nirmalts]

I am using Unbound in the Resolver mode and it works as expected. I have a problem that my OnePlus6T phone automatically adds a 8.8.8.8 as the secondary DNS, if only a single DNS server is specified. To workaround this, I added a new Virtual IP for my LAN interface (192.168.179.2), added it additionally to the DNS Resolver Incoming Interface (that is 192.168.179.1 and 192.168.179.2) and added both of them to the DHCP Server, so that the hosts have both a primary and secondary DNS. With this the phone does not add the Google DNS anymore.

Is there a more elegant way for solving this? Will this unnecessarily slow down the DNS resolution as it is the same Unbound behind both the DNS IPs?

EDIT:
Additionally, I block DNS Queries to External Resolvers (https://docs.netgate.com/pfsense/en/latest/dns/blocking-dns-queries-to-external-resolvers.html) and redirect all DNS Requests to pfSense (https://docs.netgate.com/pfsense/en/latest/dns/redirecting-all-dns-requests-to-pfsense.html). This, I guess, makes the additional Virtual IP for DNS server superfluous. What do you think is a neat approach?

[kiokoman]

i have some google home stuff with embedded 8.8.8.8 on it, I only use NAT, Port Forward to redirect all query to my dns server