Cloudflare DNS > SRV has this fields:
No idea how to input this from MiaB.
_caldavs._tcp.domain.com SRV 0 0 443 box.mail.com.
Recommended. Specifies the hostname of the server that handles CardDAV/CalDAV services for email addresses on this domain.
_carddavs._tcp.domain.com SRV 0 0 443 box.mail.com.
Recommended. Specifies the hostname of the server that handles CardDAV/CalDAV services for email addresses on this domain.