Mullvad’s DNS. It’s available for non-subscribers as well, and their privacy policy explicitly claims they do not log DNS requests in any way. mullvad.net/en/help/no-logging-data-policy/
They support both DoT and DoH, and also have various servers for blocking ads, trackers etc (if you wish to use them): github.com/mullvad/dns-blocklists
I feel dumb for not using this along with my PiHole for my home, I only have 1 PiHole machine and I couldn’t allow myself to set it up as main DNS so I used the default ISP as a second one in case my unit stopped working (because of experience).
Well, if you’re using Mullvad’s malware/ad filters etc there’s really no need for a PiHole in the first place (unless you’re doing some funky custom filtering).