Apex domains cannot have CNAME records.
Question and response
Question
dig one.one.one. NS
Answer
one.one.one. 5 NS dorthy.ns.cloudflare.com.
one.one.one. 5 NS terin.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0