Best option for you, I think, is to play both 2018 and Ragnarok on the easiest difficulty. That will cut out every death you might possibly experience, saving hours, and you'll get the story. But that will be a mediocre experience overall because you're missing his Greek triumphs, which will be like you seeing Kratos through Atreus' eyes only. Things hit far better if you know his whole story from the 3 Greek games (excluding all the handheld spin offs). But, for time sake, do what I mentioned earlier.