Rant about getting stuck at the same checkpoint for ages

I am currently trying to complete Call of Duty: Black Ops III on Veteran Difficulty, of course for an expert, this is no impossible task. I am not an expert - I complete video games to get Gamerscore, Trophies, Stickers and any collectable on offer. But getting stuck at the same checkpoint for what feels like a million times is soul destroying and makes me want to go back to college to finish by degree. I enjoy nearly every game, but the worst part about games is when they make you complete the game on hardest difficulty to complete the achievement list. Rubbing salt into the wound, the achievement is probably worst less than completing the game on Medium Difficulty. For example; Black Ops III:

For completing the game on Medium Difficulty you'll get 220 Gamerscore, if you complete it on Veteran Difficulty you will get an added you get nothing but the abilities to do the hold thing again on Realistic Difficulty which is even more difficult for an added 50 Gamerscore - in my opinion, I don't think it is worth that.

Something even worst than getting stuck at the same checkpoint is getting killed on the actual checkpoint before you are even able to move out of the way of the grenade or solider getting the world's luckiest headshot. I was getting checkpoint killed by the same grenade for 9 and a half minutes, I believe I need to have therapy sessions to make me safe to the outside world again.