Outside the cosplay-con there are some echoes that are weak to physical damage and are high enough to bring you to a fair level, like 16 or something. Remember try to do quests as the cursed girls give a lot of exp and coin when defeated, also at the end of the quest you get a boost in some stats after the reward scene
After helping pheope you could farm the frogling since most of them are weak to either physical or shock damage