[Mashiro]

@AmirGT

If you follow this guide you are only using the free DNS service of CloudFlare and no other feature provided by CloudFlare (I mentioned this part multiple times in the OP post). Therefore the SSL/TLS certificate shown for your domain is Let's Encrypt. Rather said for this guide to actually work you have to use the DNS feature only and nothing else.

If you use any other CloudFlare feature you automatically use their CDN which automatically would force their SSL certificate onto your domains. And that is a huge security risk due to the "man in the middle".

That said you obviously have to do the DNS setup part on CloudFlare yourself and not use any other CloudFlare feature while doing that part.