Apex domains cannot have CNAME records.
Question and response
Question
dig tld-nscloud.com. NS
Answer
tld-nscloud.com. 5 NS ns4.tld-nscloud.net.
tld-nscloud.com. 5 NS ns1.tld-nscloud.com.
tld-nscloud.com. 5 NS ns2.tld-nscloud.net.
tld-nscloud.com. 5 NS ns3.tld-nscloud.com.
Authority
The response has no authority records.
Additional
ns1.tld-nscloud.com. 5 A 185.136.96.102
ns2.tld-nscloud.net. 5 A 185.136.97.102
ns3.tld-nscloud.com. 5 A 185.136.98.102
ns4.tld-nscloud.net. 5 A 185.136.99.102
ns1.tld-nscloud.com. 5 AAAA 2a06:fb00:1:0:0:0:1:102
ns2.tld-nscloud.net. 5 AAAA 2a06:fb00:1:0:0:0:2:102
ns3.tld-nscloud.com. 5 AAAA 2a06:fb00:1:0:0:0:3:102
ns4.tld-nscloud.net. 5 AAAA 2a06:fb00:1:0:0:0:4:102
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0