"They did a reverse DNS sub-delegation so I control forward and backward DNS
Sentences like this are the reason most people don't host their own email and
probably never will ;) What I think is more realistic, at least in the short
term, is setting up more not-for-profit community email hosts like RiseUp,
and social enterprises like OpenMailBox, so that even non-geeks can have a
choice of email services that are not pre-pwned by The Stacks (Hotmail,
GMail, Yahoo etc).
Increasing the number of people who are competent at running mail servers for
such organisations (and others kind of federated servers eg GNU Social/
Hubzilla) needs to be a priority for the software freedom movement.
Especially sharing knowledge about how to harden such servers against
interference, whether by states, corporations, spammers, or others.