Latency isn't the important measurement — it's the actual time to resolve. This will be significantly longer than the ping latency.

Unbound, recommended for use with Pi-hole, can be configured to log this by enabling "log-replies" in unbound.conf⁽¹⁾ where the time to resolve will be logged in seconds.

⁽¹⁾ https://docs.pi-hole.net/guides/dns/unbound/ ⁽²⁾ https://unbound.docs.nlnetlabs.nl/en/latest/manpages/unbound...