Can I use cloudflare DNS as an alternate DNS server?

[codeqihan]

I am now using another DNS service provider’s DNS service, I now want to migrate DNS to Cloudflare, but because the DNS service provider I am using now has a Chinese network, I can’t migrate all to Cloudflare for the time being, I want Cloudflare to use as an alternate DNS server, I have now come up with a way, is this method feasible? ：
Create the domain name in Cloudflare first and add a DNS record
Add the Cloudflare provided DNS server to the existing DNS server
This seems to work, Cloudflare also processes incoming DNS requests until DNS server address verification is provided, but I don’t know if Cloudflare will delete the domain name in Cloudflare after 30 days, I will answer that question now.

[Chaika]

I think what you’re looking for is to use Cloudflare as a secondary DNS, which works via zone transfer using AXFR or IXFR. It’s all Enterprise land though, won’t be possible to do on any of the pay as you go plans or free.

Set up incoming zone transfers (Cloudflare as Secondary) · Cloudflare DNS docs

Without using that, Cloudflare won’t be happy if it’s not the only nameserver configured for your domain. As far as I know, eventually, it should delete itself.