As above, that’s not the right thing to do. You need to change the authoratitve nameservers. Here’s the AWS guide that Cloudflare links to that tells you what to do…
If it’s not a caching issue, which step of the doc am I missing?
Sorry slitting it into multiple messages, but more than 1 attachment/message is not allowed.
Setting NS records for the domain in the zone for the domain has no effect so does not change the nameservers. You need to do what I said and follow the instructions in the AWS link I posted above. It will not work any other way.
The message says “You may have added NS records to the DNS instead of setting them at your registrar” - which is exactly what you have done.