In my opinion, the name you use at home would be your true self and the name you use at work would be the disguise because most people put on a professional persona at work and don’t behave naturally. It would ultimately depend on the individual though, some people might feel more like their true selves at work than outside work
Also true for Superman. He can’t change who he is, a superhero. However, he can disguise himself as Clark Kent.
But back to the original question. If you’re Robin at work and Samantha at home, which one is the secret identity?
In my opinion, the name you use at home would be your true self and the name you use at work would be the disguise because most people put on a professional persona at work and don’t behave naturally. It would ultimately depend on the individual though, some people might feel more like their true selves at work than outside work