Say you have someone who died due to their throat being cut with a knife. It was by someone they were familiar with, but not exactly a friend or someone they really trusted. They get resurrected with all their memories later, and would definitely have PTSD related to knives. As I have never been stabbed or killed, how would this PTSD manifest? (The character in life was an extrovert who used humor to deflect from problems)
PTSD is often about being trapped.
If they felt trapped and unable to escape then they're more likely to get ptsd.
So, while the stab wound wouldn't cause ptsd, most likely, bleeding to death might do it.
They could spend a long time holding a hand to their neck, trying to stem the bleeding, trying to escape but having no way to do it. No hope. The phones are gone, they can't reach the door, they're trapped in their apartment or wherever in an increasingly painful body.
That sort of immobilization tends to cause ptsd a lot more than when people feel they're making meaningful progress.
That was part of why WW1 was especially horrifying for many. For most of history battles were in recognized locations and would end. In WW1 people were trapped in small trenches with the executioner axe of shells slamming around them repeatedly with no meaningful escape or way to change the situation.
So, emphasize the trapped in nature of their death after the throat slash, and that will better sell PTSD.