It is recommended that you use DNS resolver providers who guarantee your security is maintained, and don't play around with your security or privacy.
Non-profit org.
No logging
Quad9 is a non-profit organization that provides a free-to-use DNS resolver service. No logs are taken, it blocks malware websites by default, and it supports DNS over HTTPS, DNS over TLS, and DNSCrypt. Quad9 is based in Switzerland.
Notes:
Quad9 supports DNSSEC, and uses Packet Clearing House, Global Secure Layer, i3D, and itself for server hosting. The entire Quad9 platform has been designed to be GDPR-compliant from the first public announcement in 2017.
Commercial
Optional logging
NextDNS is a company based in the US that provides a free DNS resolver service. Logging is optional & is configurable via your NextDNS account. It supports DNS over HTTPS, DNS over TLS, & DNSCrypt, and features website filtering.
Notes:
NextDNS, like Quad9 (and almost every other DNS resolver in existence), supports DNSSEC. NextDNS uses the most popular ads & trackers blocklists — millions of domains all updated in real-time.
Commercial
Some logging
AdGuard, a company based in Cyprus, offers a free DNS resolver service, featuring DNS over HTTPS, DNS over TLS, and DNSCrypt. Website filtering is included, but AdGuard does store some limited logs for a limited amount of time.
Notes:
Despite AdGuard claiming no logs are taken, they do store some logs with limited information for a limited amount of time. No information logged contains any personally-identifiable information - at least that's what they claim.
Commercial
Some logging
1.1.1.1 is a free DNS resolver service owned by Cloudflare, based in the US. It offers DNS over HTTPS and DNS over TLS, along with website filtering (based on server choice). Cloudflare does log limited data for a limited amount of time.
Notes:
Like AdGuard, 1.1.1.1 stores logs on their servers for a limited amount of time containing limited information, but no info logged contains personally-identifiable info. 1.1.1.1 offers a family DNS resolver that blocks malicious sites.