as someone who frequently must switch between mac/linux/win/etc, i have had no choice but to switch to ‘natural’ because the varied OSes point you that way now. i used to spend much time learning how to customize each and every setting, but it became more hassle than it was worth to just learn the new way.
yes, i use mutt for this purpose. since most email addresses these days will only accept mail from a validated email server, you can hard code your email creds into mutt to send the email ‘from’ many email providers, including gmail