That's totally up to you. We wouldn't advise you either way - that's a decision you need to make on your own.
What we've tried to suggest here is that you use Cloudflare (if desired) by having your nameservers with their values, and then connect to Ezoic via cloudflare method. You'd be using both that way.
Alternatively, you can add the cloudflare account when your nameservers are pointed to Ezoic via the cloudflare app in the ezoic dashboard. That would have you using both as well.