you can add some challenges like getting S rank, or winning the game without healing, or winning the game under 25 minutes etc.
Viewing post in Die in the Dungeon CLASSIC comments
I think perhaps the concept of repetition isn't necessarily about difficulty, but with how there is sufficient variety to keep it engaging.
Case in point: The Legend of Zelda - Breath of the Wild with those Korok seeds... people finished the game and considered the very boring grind to be part of the gameplay. Should one really call that content? Aren't games meant to be fun?
I get your point. From my perspective, repetition is more about action than content.
so you can really turn the content into something really fun, exciting or less painful.
I didn't play the game you mentioned, thus I don't have much things to say about it, but if players keep doing exactly the same things while grinding, well it's not a surprise that content will get boring eventually.
trying difficult, not logical or even not possible things might enhance the joy&experience you will get from the content.
I like to add some spice&sauce to my meal, you know.