There's a story.
But if it's about Kratos sulking in woods for 100 years, and slowly coming to terms of what a monster he was(which i assume how it happened), then i don't know how much of a riveting gameplay you can make of that.
It would be fun if the other characters in the game were aware or became aware of what he’d done. Like Atreus, Freya, Thor, Odin, etc. Atreus would probably not quite know how to process it, so that would be delicate ground to tread.
However, the Norse pantheon should have reason to be shaking - or at least quivering - in their boots unless they’re flat out stupid. And for the love of God, I hope they don’t go the “capture son and use him for leverage” trope in order to enrage Kratos. It doesn’t get much more tired than that. I don’t think they will, at least to any significant degree; maybe a survival exercise for Atreus about what to do in a precarious situation, but not the focus or drive of the game. Just no.
Other little things like how did the urn with his visage on it get there, or who would’ve cared enough to make it? Fill in some gaps. Is Athena still really alive and kicking, like when she “visits” Kratos, or is it all in his head? Probably the former, but does she still pose a threat in some way? How has she adjusted to being left with a blank sheet of paper in Greekland?