I personally think that putting chipmixer behind cloudflare wouldn't be good for chipmixer's reputation... However, putting a landing page behind cloudflare might actually work...
I mean, by keeping chipmixer.com online behind cloudflare, you give less opportunity to fake phising sites... But you can't put the actual mixer behind cloudflare... So the "best case" sollution would be to use chipmixer.com as a portal to educate people on how to visit chipmixer on tor v3.