If the game is too easy chances are I'll zone out and "play" it, in a very inert way just watching what happens.
Not a Souls-like, but the game where I saw this at play the most is TeS Oblivion (not sure if it also works in Skyrim), as soon as I started playing it as a battlemage with the Tower sign (it takes away auto regen of magicka). Lots of content in Oblivion I felt was filler that I just went through out of inertia, but playing a battlemage with no magicka regen? Survival depends on the potions you craft and any other helpful items found along the way. Suddenly even the most boring dungeon became interesting and potentially helpful in the long run because it could contain helpful loot. Those ayleid ruins with the crystals that help a ton with magicka? Godsent rather than long and samey.
Of course I eventually leveled up enough to become OP and the game ended up being a chain of filler stuff once more, but that was several tens of hours into the playthru. But those first tens of hours were an amazing experience, where I needed to carefully plan out and scour the world for items in order to hope to survive.