Beth Is Unapologetically Black
Much of the conflict in This Is Us surrounds how the Pearson family helps young Randall shape his understanding of what it means to be a black man. While Rebecca and Jack give Randall some freedom to explore his identity, it's Beth's unapologetic confidence in being a black woman, wife, and mother that helps Randall stay grounded in his identity. Beth isn't a woman who happens to be black; she owns her skin color absolutely.
With Beth, Kelechi-Watson and the show's writers present a woman who is distinctly black, from her flawless natural hairstyles to her euphemisms, minus the caricature and stereotypes that often plague black females in media. Who else could lovingly insult Randall's "cool guy" shirt with a quip like "It wasn't cool on Sisqó in 2001, it's not cool now," other than Beth? No one.