If you want a serious career in video game programming, AAA developers/managers will generally prefer candidates that know C/C++ and understand low level detail

If you want a serious career in video game programming, AAA developers/managers will generally prefer candidates that know C/C++ and understand low level details and hardware (like explain why cache locality is the number one challenge in hitting your target framerate and what you can do about it). Generally, in my experience, somebody with only C#/Unity experience will not be taken seriously for this kind of position unless they show they understand all the other stuff (which tends to be rare). Somebody going for level and content designer jobs may get a job if they have Unity experience, however it is not because they know Unity, but simply that they show they can put something together. Most studios have their own custom in-house tools that they will need to train new hires on. (And historically, any direct scripting not in the custom tools is done in Lua.)