I haven’t read a ton, but as of now, I would have to say Goodbye, Eri. It is a very beautiful story and the only piece of media that has made me feel a wide array of emotions in such a short amount of time.
To add to that, Fujimoto’s art here is leagues above his work in Fire Punch and Chainsaw Man. I won’t go into much detail here so as to not spoil anything, but it’s definitely not for everyone. I can see why people wouldn’t enjoy it.
I was not a fan of Fire Punch. It showed a fair amount of potential in the beginning before destroying all of it about 20% in. My problem may have been that I did not like the main character at all and didn’t care for his motives. I couldn’t be bothered to care that he was constantly burning alive and that he'd never get to have sex with his sister.
Also, the troon side character was a little interesting, but it never goes anywhere with her. Nothing ever takes off with the story, and that almost seems like the point of it by the end. Nothing matters and nothing ever happens.