c # – What is missing in my skill set to become "full stack"?

I am a somewhat junior developer with 4 years of experience. My first 3 years were basically SQL database developers, last year I took .Net / c # developing small console applications that interact with databases.

I would like to become a developer of & # 39; complete stack & # 39; What else do I need to learn and how?

Things that come to mind: basic web development (HTML and CSS, JavaScript) and a platform as a service such as AWS.

But how deep do the technicians need to learn, is there something else that I'm missing?