While she could become the top class adventurer but she don't want to. All she want is just a regular life, stable job working 9am - 5pm, relaxing at home after work, eat, sleep and then repeat.This world must not have much of a banking system. She could be a top class hunter for a year and then just retire.
Nah, none of the explanations make any sense. Given what has been said about adventurer pay, she'd only have to work for a very short time and because of how casually she one-shotted the boss, it's not like she'd be in any real danger. Moreover, it's established that she periodically kills bosses already.While she could become the top class adventurer but she don't want to. All she want is just a regular life, stable job working 9am - 5pm, relaxing at home after work, eat, sleep and then repeat.
If she become adventurer, sure she can be the top very fast but that mean she has to fight with monster regularly, which she doesn't want to live like that.