There’s a saying you want someone dead you shoot them in the head.
You want someone to suffer you shoot them in the gut.
It can be a slow miserable death as your body slowly goes into shock and dies. I’d imagine a blade would have a similar story.
There’s many critical structures to avoid such as a network of nerves sometimes referred to as angel pasta. There’s arteries and your gastrointestinal tract. Any of these being stabbed can game over or irrevocably alter the course of your life.
Your best bet is a stab that doesn’t go through your core but parallel like through the fat layer of your stomach.