

This would be called Emotional Detachment or Emotional Blunting. It is associated with several mental health issues, such as anxiety, depression, and schizophrenia, and it can be developed as a coping mechanism for a stressful or abusive childhood or past. It can also develop as a side effect for some medications, so it could be worth looking into a change in prescriptions if you think that could be relevant.
That is to say, it is an abnormal mental state, but you are not unique in this mindset. You should strongly consider reaching out to a mental health professional to see if you can work on this as it is likely to lead to more isolation and a worsening of your overall well-being.
Yeah, I like to think of out more as a spotlight than a mask. You’re choosing which aspects of yourself to draw attention to rather than hiding yourself behind a persona.
That is, unless we’re talking about the masking that neurodivergent people talk about wherein they put conscious effort into hiding their essential nature in order to fit in.