You don't always have to only play with difficulty that's handed to you on a plate; you can create your own difficulty.
But there's something unsatisfying about having to limit yourself to find a challenge. I didn't even try that hard to min/max my characters, and I found maybe 3 fights after level 10 or so hard enough that I had to retry them multiple times. But I don't want to have to impose arbitrary rules to actually find a challenge. I want to feel stretched to the limits and be able to use everything to my disposal without feeling guilty for cheesing the game. They really need an extra hard mode that starts you with negative resistances and increases damage of enemies by a lot (especially the later enemies. Early game balance is pretty good.)
There's also a lot of stupid AI behavior that makes a fight go from challenging to a joke in a couple rounds. Fire enemies attacking your fire elemental and healing them, for example. Or attacking charmed enemies with far too much enthusiasm. But nerfing resists and rubies by a lot alone would actually make combat more satisfying.
