Elite: Dangerous PvE - Mobius

Then you should check out the No Man's Sky. They have those fancy Journey Milestones for like every possible action.

P.S. And you'll also know what does "grind" really means

Yes from back when you had hand operated mills.
Working the grindstone was backbreaking, never ending labour.

If you are alluding to sexual activities.
Well if you find sex a grind you are REALLY doing it wrong.