first@firstlast.example seem rather redundant; like saying "John John Doe". I guess if it was a business it would make more sense; like "John, owner of John Doe Inc." and "Bob, assistant for John Doe Inc." but for a personal domain... eh.

Similarly mail@ email@ seem 'too obvious' since.. of course it's email? Directional local parts like talkto@ to@ only make sense for inbound-only or outbound-only.

I do like io@! hello@, contact@, note@, or communique@ also seem more neutral but at this point I'm getting dizzy lol.

first@last.example seems more simple in retrospect but also harder to get.