You could explore the game's side quests and collectibles. There's often a lot of hidden content that adds to the overall experience.
After finishing the God of War story, you could read related comics or novels if they exist. Or, just take a break and come back later to appreciate the story anew with a fresh perspective.
Maybe try replaying it on a higher difficulty level to challenge yourself and discover new strategies. You could also look for online discussions and fan theories to deepen your understanding of the story.