the base game is fun, but the new area is pretty badly balanced with XP

I was only level 13 when I beat the base game and went off to the new area, just to find that the boss there is level 30...It would take me literally fucking forever to get to that level due to quests not giving xp and enemies giving barely any XP, forcing me to just use Cold Blood and Pyroblast and hope that kills them in one hit before I get destroyed

I had to do exactly that to beat the Arena, and I was only level 15 after I beat it :/