Cooking is one of those things with very narrow bands between the lowest skill levels. There are only a few relatively simple lessons to master and then, quite suddenly, you’re very competent. A little more practice and you’re pretty much at the “really excellent home cook” category.
Making a dish that “passes for professional” just means that you’ve perfected a few specific techniques and have found/inherited/developed a truly excellent recipe. There are people who have opened (successfully or not) restaurants and food trucks with just a handful of recipes like that.
Passing beyond that level gets into developing encyclopedic knowledge of preparation techniques and food interactions, memorizing dozens of baseline recipes and their variants, perfecting complex mechanical skills through endless repetition (shucking oysters, butchering meat, forming a baguette) and so on. That’s what culinary school is for. It’s about a lot more than making a few tasty dishes.
Like Chefguy, I’m good enough to cook most anything that I fancy and smart enough not to try it professionally.