Before changing domain nameservers at domain registrar:
Lower your TTL for DNS records at your current DNS provider/cPanel/Web hosting to 300
Check your current nameserver TTL (4hours or 24hours)
Add your Website to your Cloudflare Account
All the DNS records or import them with a single click
Disable DNSSEC and remove DS records
Wait for few hours or a day
Once ready, change the domain nameservers at your domain registrar and let it use as much time the DNS propagation process needs to finish
We cannot manage this, therefrom it’s with the reason set to 24h due to the possible abuse and further cases which happens and to have some room left for all DNS servers to catch the updates and cache the DNS records as well.