My stack is postfix, dovecot, slapd for accounts, SoGO for web mail, calendar and task and contact management. Syncs to my phone via davx and just works out of the box. It’s multi domain and my small company even sells hosted email services.
Rspamd for anti spam and dkim. Use a free email testing service to confirm SPF etc are setup correctly.
Also make sure you have regular backups and up to date lets encrypt certificates.
The legislature and violence monopoly are there to ensure all people have legal recourse instead of needing to turn to violence. If you corrupt that system and use it to oppress the masses, they become violent.
I neither agree with, nor condone violence, but it does not surprise me at all. Just surprised that it took so long.