before you want to crucify me read all.
Nezuko doesn't talk at all like WTF this is just so bad, her not talking because it may strengthen her demon powers is just an excuse to not develop her character, for me her not talking is like "somehow palpatine returned".
Tanjiro is a very bland character and has no remarkable personality other than being kind, he doesn't even shown any sign of PTSD for witnessing his family die he looks very happy all the time. he should look depressed, angry and have signs of ptsd, it just make him so unrealistic he is only loved because he is cute.
And the worldbuilding is very bad, every place is just a fighting place with a brief explanation. muzan only "conquered" japan not the rest of the world which makes him a much much worse villian, japan should have been a place where you could die at any moment, not the only place where demons live.
If we wait 5 years after kny anime ending it will be considered a forgotten anime.