Review Detail of ven_ren in Reincarnated in demon Slayer as my first world (rewriting)

for a while i could not put my finger on why i dislike this fic so badly, know i realize its because the characterization,writing,background details,dialogue is all trash. none of the harem feels like the actual cast and any attempts at writing them usually has heavy flanderization. how do they so easily fall in love with the mc?. the dialogue itself is even worse as none of the words said feel natural and are 100% forced. the background details are so sparse that i usually have to refer to my own knowledge of the locations or simply guess. this story is the embodiment why i hate harems.