Yes, you need more PEN. Since you can only force your progress approximately 1/3 of your initial PEN.Some stages and dungeons cant be cleared. Why tho? Do I need more PEN? or do I smth wrong. Cant clear 12-25 for example
i.e if you have 50k PEN the you'd most likely stuck at stage/dungeon that requires 65k-70k PEN.
that said, if you want to progress it is recommended to use "1shot skill" rather than clear wave. Because clear wave is only applicable for online farming.