Or: use a different email provider.

My assumption is that the pattern you describe is possible/doable on certain scales and in certain combinations of technologies. But doing this across a distributed system with as many nodes and as many different nodes as CloudFlare has, and still have a system that can be updated quickly (responding to DDOS attacks for example) is a lot harder.

If you really feel like you have a better solution please contact them and consult for them, the internet would thank you for it.

That’s a math article