I'd recommend a balanced build, I never had trouble distributing my points equally. For example, look at my balanced build XD...
View attachment 2935669
Jokes aside, I hardly struggled with a fight by spreading my points equally, only annoy was the occasional uses of Cleanse Lust to compensate Belle's burger perk downside. However, when I got to fighting both onis (yes, I never fight them one at a time, and the first time I do fight them with Kotone's debuff perk active granted by her route), I was at around level 60, so I think people reaching the labyrinth at a level lower than 90 are just "speedrunning" their game. Or maybe they've got a way easier time by just sticking to a couple of skills and spilling points into their related stats. I'm not quite sure.
But given Bengamen's current build, my tips described on my previous post still apply, because of his focus on power and allure. Maybe start giving points on luck, to increase critical chance? But I reckon he should be fine if he follows my cycle and heals when needed. IMO, a balanced build makes your game a lot easier to play through.