Existential angst is portrayed and experienced as individual suffering. In white-majority countries, white people tend to think of other whites as individuals with individual identities, but they tend to think of people of colour as a collective with a collective identity. Thus, white people from white-majority countries tend to think that people of colour cannot experience existential angst.
However, the problem is that people of colour think of ourselves as individuals with individual identities. (Or at least I do, and I assume that other people of colour do too until proven otherwise, because I consciously reject stereotypical assumptions of questionable origin, not because I actually have access to the minds of other people of colour.) Individuals of colour can experience existential angst, and in addition, our consciousness of ourselves as individuals regularly clashes with our consciousness of how society views us as a collective.