This is addressed with commitments and third party audits assuring 24h retention for IP logs. There are other conversations in this thread surrounding the viability of those audits, but that's somewhat of a tangential debate.
This doesn't answer whether or not cloudflare will be able to protect against someone intercepting their traffic and recording dns lookups independently, but that's a problem for any dns provider.
Especially since they advertise being actively involved in certain political movements and promise to defend those ones. That's a scarily biased attitude for a DNS. How does someone's sexuality have anything to do with IP address lookups?
Sorry, but I don't trust Cloudflare with anything anymore.