A main character can have any morality whether that be good or bad. Hero's journey is a template for writing a story as such, but it's an informal fallacy to say all main characters are heros.
An ideal fictional hero would be one who has relatable qualities and isn't a 'dues ex machina'. One who makes it out alive just because. I prefer one who works hard to achieve their goals in selfless acts.
Guts from berserk personally is my favorite hero. He starts off his hero's journey as a knight/sword for hire without a purpose and slowly finds his purpose when forced to join a mercenary group known as the band of the hawk. It's interesting because for once, we see a character find his reason for his existence rather than have one in place for him.
