i would consider 4 years to be

• too long amount of time for a job you don’t like (it took you 4 years to realize that you don’t like it?)
• too short for a job you are committed to (you give up only after 4 years?)

After almost 4 years, I find myself lacking the energy and enthusiasm I once had

once i had? energy and enthusiasm he had only 3 years ago?! When i started reading the article i was expecting 15 years, 20, 30+