6min/km is an average pace, so I do wonder why you still hate it? Have you looked into your cadence? Are you steps too long or the shoes too hard? Or do you have to run through post-apocalyptic ruins?

I'm not sure. It's not that I feel a huge discomfort or that anything hurts. It's just kind of pointless I think. I love martial arts and parkour, though. Maybe because the exercise is not the thing itself, but a byproduct of the activity?

It's very much not pointless. It can be difficult, initially, to reason about and iterate on activities that don't confer immediate feedback. These types of activities build effects over long periods of time, but everything we know says they're good for us. For example, it's hard to regret being overly winded during occasional martial arts or parkour when you're not.