Cloudflare is described as 'Protects websites with front-end proxy, dynamic DNS, CDN, and firewall; blocks DDoS and targeted attacks, optimizes traffic, and analyzes threats' and is a very popular CDN in the network & admin category. There are more than 50 alternatives to Cloudflare for a variety of platforms, including Web-based, SaaS, Self-Hosted, Linux and Windows apps. The best Cloudflare alternative is DNS4EU, which is free. Other great apps like Cloudflare are Anubis, DigitalOcean, Cisco Umbrella and Duck DNS.
Cloudflare is a CDN, Google Cloud DNS is a DNS admin console. Completely unrelated.