I have a CNAME record in cloudflare pointing to an ALB, e.g: hello.exampleserver.xyz
I plan to delegate hello.exampleserver.xyz so the CNAME record in CloudFlare needs to be changed to NS record. The hello.exampleserver.xyz zone will be delegated to Route53.
On Route53 zone I will have an A Alias pointing to existing ALB.
My understanding this process will require delete and create record.
Are there any potential downtime where hello.exampleserver CNAME record is removed but the NS is not ready yet so Cloudflare DNS will gives NXDOMAIN?
How to test this change and monitoring the changes globally?
Are there any other potential downtime risk doing this change?