I don’t think it is a subcategory I think it’s the term you’re looking for.
The actual phrase has its origins in a financial sense but the way it’s used nowadays is much more broad. You can invest time, money, emotion, identity etc and it’s still the “sunk cost fallacy” if it keeps failing and you keep going.
DnD somehow tries to sell itself as a combat simulator. And yeah, it’s combat system is more fleshed out than many other roleplaying systems, but at the end of the day a lot of the combat interactions are down to the DM to decide so it ends up being a normal roleplaying game with the occasional stumble into a waste-deep muck or rule interactions for what ended up being almost no reason.