If I focus on Y & Z until the result is passable, do I then do the same for X? Or do I try hard with X (time which I would enjoy), even though it won't be appreciated? At that point why not work on a personal project which would give me satisfaction, instead of working.
That's a million dollar question. Going by triathlon rules, train to where you can be competitive on your two weakest legs, and then hammer home your strength.
In MBA circles they talk about how organizational effectiveness enables competitive advantage. I.e be operationally good in all areas of your business but align your goals behind being great at one that differentiates you.