Debian 10 with Hesia works just fine. My VPS provider has provided me ns1.namezone.ru / ns2.namesone.ru but as well says I need to set DNS BIND Zone Transfers.
I did all correct in /root/dnsmgr/dnsmgrupdate.conf
1 would probaly been easier to solve, but not sure if it is needed, usualy also-notify should do the job - but I do not know how exactly your providers requirements.
Probaly you mean deleting a webdomain does not remove dns and mail - this behaviour is expected. Because sometimes you want to delete a web, but no mail or dns (for example moving web to another server) - this would cause a data loss.
Big NO on that! To delete the DNS and Mail Domain separately is just clicking two more buttons. But if someone loses their DNS zone or Mail files, they will get into a lot of trouble for sure. And what’s more, only a few people read (and understand) warning messages, before clicking