Apex domains cannot have CNAME records.
Question and response
Question
dig arcade.ch. NS
Answer
arcade.ch. 5 NS ns1.arcade.ch.
arcade.ch. 5 NS ns2.arcade.ch.
arcade.ch. 5 NS ns3.arcade.ch.
Authority
The response has no authority records.
Additional
ns1.arcade.ch. 5 A 46.22.21.30
ns2.arcade.ch. 5 A 46.22.22.30
ns3.arcade.ch. 5 A 176.97.158.100
ns3.arcade.ch. 5 A 192.174.68.100
ns1.arcade.ch. 5 AAAA 2a02:1368:1:47:0:0:0:53
ns2.arcade.ch. 5 AAAA 2a02:1368:1:48:0:0:0:53
ns3.arcade.ch. 5 AAAA 2001:67c:1bc:0:0:0:0:100
ns3.arcade.ch. 5 AAAA 2001:67c:10b8:0:0:0:0:100
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0