@Gargron
have you tried shouting at the computerer?

@Gargron I don't know if it's what you're asking for, but you have DNSperf that test them. When I changed to Cloudflare the difference was noticible when testing sites with GTmetrix and Pingdom.

https://www.dnsperf.com/

@Gargron Make it query a very long url so it takes a while for it to say the whole thing and then time it with a stopwatch.

@Gargron

DNS Monitoring With Nagios

I don't remember if this does specific DNS performance test but you have source so it is at least a reporting framework.

https://www.nagios.com/solutions/dns-monitoring/

@Gargron long time ago when I used Windows I used this tool to measure DNS server performance: https://www.grc.com/dns/benchmark.htm The page says it's compatible with Wine, so it's worth giving it a try. Bonus cool points that don't matter - it's just 147KB and written in assembly :)