If you want to read a manga that make you think, you should try Neji no Hitobito Neji no Hitobito is a short manga about philosophy, yep that seems strange but this is cut by episodic chapters that aboard philosophic concepts such as identity, values, work, love or the use of thinking But even if the context is interesting, the form is kinda weird, with unnecessary/forced romances or fanservice tropes The manga brought me some way of thinking I never apprehend and that's cool, I also liked some metaphors and some non-philosophical subjects evoked. The bad points are the art, kind of basic ans sometimes mediocre, even ifit's still readable.
Personally, I disliked some subjects because I wasn't agree or because the conclusion brought by the author was weird

If you want to discover some cogito and ways of thinking, It's a good manga for you, if you aren't interested in philosophy, I don't recommand you to read that !