i dont really feel like this manga is necessarily inherently depressing or depicts someone on the margins of society. a desire to escape one's daily life is fairly common, especially if you feel unrecognized and unwanted in your social interactions. i think that its pretty impressive for someone to recognize that their life is making them unhappy then take concrete steps to change the factors in their environment that are causing that unhappiness. its braver to attempt to change one's own life, if not the world instead of rationalizing own misery by saying things like, "that's just how adulthood is" or "there really isn't any other way" while allowing themselves and those around them to suffer indefinitely.
like idk itd be so much more depressing if she never thought to leave her job and just never actually felt the absence of fun or satisfaction in her life until she retired. esp considering that workaholics who stick with their meaningless jobs until they hit retirement age for no reason besides they cant think of anything else to do(if they make it to that) tend to die pretty soon afterwards