This is not a fun subject. Here is my concern:

Long dying times. Cringy, and in a few anti-cliche books that I read talking about the cliche. Unless it was a non-fatal wound that is festered, don't. Sure that it is painful. But often in real life, people only have a moment. Not enough time to write, monologue, etc.

Head blow and penetration is often an instant killer. Torso and major arteries have barely any time. Unless you have a precise knowledge of anatomy, knowing where to place injures. Torso injuries is often a fatal one that deals with extreme amounts of pain. A character can't focus too well under the duress by pain.

Want a message of a dying or dead character? Here is my ideas:

1. A written journal. This one can happen in real life. A journal detailing the character's life up to the day of the death can an opportunity to leave a long message. Far-fetched? Think about how the character misses the lover.

2. Letters. Old fashioned but it makes such a good idea to message how much the character loves.

3. Message from someone else. Even though it is corny, a person who the character gives the message can get it from anytime before the character is fatally injured or dead.

Even though it is short. That is all I give advice on. Research if you need help on this subject.