It is known that most of the leveling problems a player faces after leaving Tenet, is the Gateway Route area and It’s parent fields like Overlong Bridge and stuff, and the highest causer is that beside the quests there takes a lot of time to complete, either by bad mob positioning, or because the objectives are annoying, all npcs gives exactly 1 Exp Card Lv 3 as reward for completting them.
With that kind of reward, I don’t even want to remember how It is to do quests in the Dungeon at the way of the quest line.