So I've played AC Valhalla for almost 140hrs+
I completed story and every regions of the all maps are 100% (including Norway, England, Vinland, Skye, Asgard, Jotnheim). I completed everything in this game and yet i can't reach power level 535 (which is max). i'm stuck at 523 and Reda quests don't give much XP. Those Items at shops aren't always available too. And I don't want to buy any DLC or XP Boost.
So what can I do to reach Level 535 in base game? I've literally completed everything (Wealths, Mysteries, Collectibles, Treasure Maps, Raids, Missions ,etc).