Honestly, the Nietzsche quote made me reconsider what this manga is about, and I think it more or less is implying his underlying philosophy about the manga as a whole.
Nietzsche believed that life in his time and the future in a world increasingly becoming secular with a society becoming less dependent on religion, clear institutions promoting beliefs and clear objectives in life, and as people realized that they generally would have no purpose except for what they made of themselves, those who were more naturally subservient would fall below those who had stronger wills. Therefore, to replace the general void modernity has caused by moving past regressive institutions that promoted herd-like mentalities, Nietzsche believed that mankind must find new things to fill the void, such as art, culture, etc. and new purposes for man to pursuit in life.
In this sense, FMC is following the same internal struggle, as the apparent suicide of her lover seems to have left her goal in life meaningless and without purpose, and so she pursues a life that is, at first, characterized by trying to end her, and then to then pursue what brings her joy in life, which Nietzsche believed that man should ultimately do to seek fulfillment, rather than to carry out a meaningless existence.
I hope this is where the story is going in terms of themes because it could be interesting to watch