As far as replacement options for this module, you currently only list "drupal symfony mailer."
Please consider also listing this one: Symfony Mailer Lite ( https://www.drupal.org/project/symfony_mailer_lite → )
While symfony_mailer may be the way forward, not everybody will need all the extra configurations and policies, etc. Also, I personally found several issues with it that were hard to fix, and needed coding and patching. Certainly not all users would be able to do this.
I then switched to the lite version, and it just worked flawlessly, both for contact-emails AND custom themed emails (hook_mail, etc.)
It basically appears to be symfony_mailer (including the transport settings), but only the bare necessities, and can be used as a drop in replacement to the already existing mail process, including using the old "mailsystem" module that most users will have, and hook_mail. I found it so much simpler to use.
Yes please! Using symfony_mailer_lite is a terrific alternative which does not require re-coding a pile of hook_mail and hook_mail_alter's.
An easy drop-in replacement, instead of a completely different approach.