Well recently I have done some grinding so now I'm level 72 and have 12sp.
Also, one thing to keep in mind in the labyrinth levels is that the enemies actually "level up" each subsequent time you encounter them, thus you actually need to prioritize getting the keys and getting away, whilst only engaging in actual combat whenever they directly block the way.
Considering that they start at extremely-easy levels at first (~ lvl 20), and you are level 72, I figure you ended up encountering Beris too many times within the same Labyrinth, leading inevitably to her being too strong to take care off. As HumanRug said, you should be just fine at lvl 72 for the most part.
Really, the only 2 Fights within the current game that I see as "SuperBoss"-level (and requiring some dedicated grind to overcome properly) are the Sofia fight at her current strongest, and the Venefica fight (the version in which you fight her alone, in both her phases).