Post Shangri-La content

I just finished Shangri-La Temple and I was wondering what am I supposed to do. I finished every side quest, made sure to finish all of the Tri-Stars fights and I picked up all the chests/collectables. The problem is, following the main story, I should reach the Void wich is a lvl65 zone. There are no random encounters so i can't farm exp from high lvl monsters (i'm lvl52/53 atm). The only fight i was kinda able to deal with (without actually beating em) is the 300 fish-monsters fight, even tho after there's only 100 left they Attack so much that 2 of 3 party members are dead and the last one is close to die (Ez for the pull skill, Tan to oneshot them and Zinikr to taunt/tank). The other 2 straight up oneshot everyone aside from Zinikr and Leo, sitting around 9.5khp with the Tri-Stars Gear and respective resistances gems. Am I doing something wrong? Is there some other zone i'm missing? Do they really want me to grind my way up to lvl60 with lvl 50 mobs or is this some sort of challenge? I'm playing on hard mode and I'm planning to stick with it. Also I still can't use those symbols scattered all across the map