Comme un arrière goût amer

I absolutely adore this author, and their drawing style keeps getting better, but why do I feel like their recent stories like this one, and Dear 00 are missing something ? Idk it's particularly evident in Foul's Start, but I get the impression that the plot doesn't move forward, which leaves very little room for charachter develoment. The plot itself doesn't seem to be a plot at all.... Idk man.