The following topic was closed 3 years ago but there is still very much a need for it: https://wpforo.com/community/how-to-and-troubleshooting-2/email-reply-via-email/#post-56335

At the time @robert mentioned such an email system within Wordpress was impossible but a lot has changed since then (although I think it could've been done back then as well) especially with Fluent SMTP and other mailing server plugins.

@vinnyusestrict you mentioned you were working on a solution. I take it you shelved that idea?