About Pillars of Eternity 2 though I have heard it is so hard (and I am not expert on POE 2 builds) so will not use hardest difficulty in Pillars of Eternity 2. On the other hand POE2 is not even DnD rules though it reminds of it more or less.
What? No. PoE2 gets very easy, unless you mod it. The very start is as hard as it gets, and two major encounters on the opening island can test one’s patience - but after that things get considerably easier. The game has a bit XP bloat problem, 1/3 through the game you will start feeling over levelled for the content.
DLCs raise back the difficulty, so if you play on POTD those can be a rude waking call if one cruises on without learning mechanics or finding synergies. There are also couple rather hard “megabosses”, but their only purpose is to provide ultimate combat test to your party, and there isn’t much point of fighting them otherwise.
Personally I want to do another run of PoE2 with Deadly Deadfire mod, which I hear spices things up, but I want to finish Wasteland3 first, and I just can’t connect with that game.