The only way to be wholly content and happy doing something is if you have considered your alternatives and decided that doing this thing, right now is the highest possible use of your time.
Skipping the consideration spoils it. Harboring resentment spoils it. Feeling forced to do it spoils it. Feeling guilty spoils it. Rushing to just get it over with spoils it.
It does not have to be something other people would praise you for; it only matters than you know you made the right choice. It can be whatever you want, as long as it's thoughtfully, intentionally chosen.
Almost everything we do is chosen for us, even leisure is mostly dictated by algorithms telling us what to watch, read, or listen to. We rarely get recommendations from friends anymore. When you seek harmony with the universe, be careful about trusting your success to a machine.
Done properly, you must balance measuring progress toward a goal and also be perfectly content with doing what you're doing forever. This is impossible to do perfectly; you must try anyway.
When you get it right, minutes feel like hours and hours feel like minutes.