One thing you can do is to upgrade all of your equipment to its maximum level. You've probably acquired a lot of resources during the main story, and now is the time to use them. Maxed - out equipment can give you an edge in any post - story challenges or if you decide to replay parts of the game.
You could explore the side quests and hidden areas. There's often a lot of additional content to discover.
One thing you can do is upgrade your weapons and armor to their maximum levels. You can search for the rare materials needed for the upgrades in different parts of the game world. This will make you even more powerful for any potential post - story challenges.
Engage in combat challenges. The game has various combat arenas where you can test your skills against tougher enemies. You can try different combat strategies and weapon combinations. This not only helps you improve your gameplay but also gives you a chance to earn more XP for leveling up your character.
Replay the game on a higher difficulty level. It will give you a whole new experience as the enemies will be tougher and you'll need to use more advanced combat techniques.
You can explore the realms more thoroughly. There are many hidden areas that you might have missed during the main story. For example, in some of the more remote corners of Midgard, there could be secret chests with valuable loot like new armor pieces or enchantments.
Maybe go for a new game plus to experience the story with different choices or challenges. Or you could read up on the lore and background of the game to deepen your understanding.
Maybe it's time to delve into fan theories and discussions online. Sharing and hearing different perspectives can deepen your understanding of the game's story.
You could explore the game's side quests and collectibles for more content and rewards.
Find and unlock all the fast - travel points. This will save you a lot of time when you need to backtrack or quickly move between different areas of the game world. It also ensures that you can easily access any place you might have missed something important, like a hidden chest or a side - quest giver.
Explore all the hidden areas. There are often secret chambers and passages in the game world that contain valuable loot like rare armor pieces or powerful runes. These can give you an edge in the final battles of the story.