What kills enjoyment it's not proffesionalism but efficiency. You stop exploring new things and start doing things the fastest and least effort consuming way. You stop wondering what new cool things a technology could offer and start thinking what's the shortest path to a functional product.

Being playful is the opposite of that. Being playful is about going out of your way to explore a new thing, setting your curiosity high and your expectations low, and coming back with a new experience. Let it be a spark of excitement or a total bummer because that new thing turned out being crap.

But don't expect that to happen in your job. Any company will always optimize for profits over cool tech. Even if you only have 1 hour a day to spend in a tech hobby, that hour will be more exciting then the previous 9.

Another problem is that, when you have a solid knowledge about the foundations, there's a tendency to disregard abstractions or quality of life advances. If for every new language you say "It's slow and heavy compared to C and its advantages are crap" well, you are killing your excitement yourself.