Michał Górny (he/they) ∞🙀🚂🐧 (npub1r9j…4ppx)
3, the alias approach is probably best.
Set up a script so you can just enter an alias and populate it to exim / dovecot / mailer config and /etc/aliases.
Or, install hestia control panel to manage mailer and use the web panel gui.
Either way, $profit$