Integrate Cloudflare WAF solution with AWS Load balancer

Is it possible to integrate Cloudflare’s Web Application Firewall (WAF) with an AWS load balancer endpoint without having to migrate all DNS records from AWS Route 53?

Yes, with a Business or Enterprise plan, you can do a Partial/CNAME setup: https://developers.cloudflare.com/dns/zone-setups/partial-setup/

Otherwise, no.