you are getting things confused
for an outside email being filtering it can be done at any point on any node, whether that be the dns node of the destination node
when you say manual
you run your node,
YOU control everything
if yourself run a dns node, you can control everything at that point
if you simply run a normal node
you can control everything at that point
(whether the dns node does anything or not)
ANYONE can run a DNS node if they have a static IP
the only bad actors in your scenario
are spam email addresses and spam IP's or other known bad IP's
these can easily be filtered at the dns level
(and at any level)
NID's will not be sending you emails
Amail is only a bridge to the old world
it is not how ANNE users communicate within the ANNE network
just a bridge to allow emails in and out if you desire
if you do not run any node
and simply want zoide@anne.network
all will be done at dns level node