English has lots of axes to represent this difference, I offered two in my post:
amateur versus professional: King was paid so he's a professional filmmaker.
bad/unskilled versus good/talented: King showed himself to be a aesthetically bad/unskilled filmmaker.
You are offering a third axis:
"one-off" versus "career": King so far has not made a career of filmmaking and only made the one film.
In English yeah, we do tend to assume the first axis (amateur versus professional) as the "default" axis. I think this is a very useful axis to use as the default: it's the least gatekeeping and the least subjective. Have you been paid anything to do that job? Congratulations, you are a professional at it. You've done the job. Otherwise, you are an amateur, keep trying you'll get there some day.
"one-off"/"career" is an axis with more subjective judgments. (How many films does it take to call it your career? 2? 14? If you deeply and academically study films your whole life but only make one masterpiece, is that not a career effort?) I shouldn't need to explain how good/bad, skilled/unskilled are deeply subjective.
