That's cool thanks for the link. I am doing exactly the same except I run my own mail server (postfix as well!) in a dmz but that will come in handy I think.
Have you looked at @kahn-hubitat's sendmail? He's been actively developing his version so that might be something to consider.
I am using Node-RED for my rules etc - it has built in email support so I can securely send and notify based on HE events.
