So unless learning C somehow causes permanent disability I will have to respectfully disagree.
C sort of does cause a disability (not really a disability, this is a useful skill!) in the sense that now you're actually thinking about how a language feature works in the hardware, which is not something you necessarily need to do for higher level languages. The moment you ignore all this it's likely that the language will make sense again. Of course, like I said, this is all subjective. The solution to "I can't use async/await because I don't understand how they work" is basically that you pretend that they're magic, and try to figure out the internals on the side. You need not understand how things work under the hood to use them, though it is an extremely valuable skill to know what C#/JS/etc end up doing at the lower level.
It's a sort of "ignorance is bliss" situation.
It varies from person-to-person though. It's not specific to programming either. When I was a physics student I personally would be easily able to define layers of abstraction in my mind and work within one layer, even if I didn't understand another -- you ignore how the other layer works and assume that it is magic (while simultaneously working to understand the other layer). One of my friends could not do this -- he had to understand rigorously how the theorems worked all the way down. As you can imagine, this required a lot of effort. It meant that he always had a thorough understanding of the topic at hand, but often meant that he spent a lot more time to understand something and had no middle ground to choose.
For me, this has carried over to programming. If I'm dealing with a language like C or C++ I will try to understand how everything works on the metal. When I first learned about C99 VLAs I spent an hour mucking with a debugger and inspecting the stack. When I realized that C++ had function-local initialized statics I spent many hours digging through C++ spec/implementations to understand how it worked (http://manishearth.github.io/blog/2015/06/26/adventures-in-s...). These are things at the same abstraction level as C/++ which I must understand to be able to use them.
But when I'm dealing with languages like JS, I can operate perfectly fine without knowing how they work. Indeed, when I first learned about generators, I was able to use them for quite a while before I learned how they work. I still want to know how things work (and generally dig into it), but it doesn't block me from proceeding if I don't.
This is not how everyone approaches languages. Like I said, it is subjective.