Discovery is a story about the limitation of promotional opportunities for black women.
The main character in Discovery is a black woman, and a central theme of the show (through season 3) is the fact that she's not the Discovery's captain. Instead of Burnham, the Discovery's captains are a white man from a mirror universe, a white man who's actually captain of the Enterprise, a Kelpian man who worked with Burnham on the Shenzhou, and a white woman who was an ensign. In contrast to other Star Trek shows, before getting promoted Burnham has to end the war, escape the mirror universe, become a timetraveling angel, permanently bring the whole ship into the far future, and identify the cause of the collapse of galaxial society. (And then the Kelpian man has to go off-duty.)
Not everyone gets to be promoted, but if you're a black woman, it's you in particular who doesn't get to be promoted.
That is a problem in reality, and it's not worth ignoring just to pretend there's no racism or sexism in a fantasy universe.