samba - Jun 2022 - Samba, Bind DLZ, and DHCP

How do I create an MX record? What is the syntax for that?

I need to know if there is a way I can tell Bind with DLZ to accept 
normal Zone updates with Bind DLZ. I would like dhcpd to be able to 
update the zone in the manner it had before. Can Samba or Bind still be 
told to allow updates?