“The Vanishing Half” by Brit Bennett: Is this a novel about a light-skinned black “passing” as white, or is that just a cover story for multiple personality?

“The novel is a multi-generational family saga set between the 1940s to the 1990s and centers on identical twin sisters Desiree and Stella Vignes. The two light-skinned black sisters were raised in Mallard, Louisiana, and witness the lynching of their father in the 1940s. In 1954, at the age of 16, the twins run away to New Orleans. However, Stella disappears shortly thereafter. In 1968, Desiree leaves an abusive marriage in Washington, D.C. and returns to Mallard with her eight-year-old daughter, Jude. Jude grows older and moves to Los Angeles through a track scholarship at University of California, Los Angeles. While working part time at a bar in Beverly Hills, Jude sees a woman who appears to be her mother's doppelgänger. The woman is actually Stella, who has been passing as white.” —Wikipedia

The New York Times book review sees this novel as an addition to the American genre of novels about “passing,” except that it mentions the author’s being influenced by Nobel Prize novelist Toni Morrison (whose work is pervaded by the issue of multiple personality) (see past posts here), https://www.nytimes.com/2020/05/26/books/review-vanishing-half-brit-bennett.html (but, it appears to me, The New York Times Book Review ignores the issue of multiple personality in Toni Morrison or anyone).

I have just begun this novel, and it is risky to initiate an interpretation based on the way the author has phrased something at the beginning, but since an author might use identical twins as a metaphor for multiple personality, I noted the following:

“Being half lost was worse than being fully lost—it was impossible to know which part of you knew the way”…“What now, she [Desiree] asked Stella in her head. Where do I go? (1, pp. 15-16).

1. Brit Bennett. The Vanishing Half. New York, Riverhead Books, 2020.

Added 8/30/20: I do not doubt that the author intended to write about "passing," but am wondering if, in spite of her intention, there is evidence, psychologically, of her inadvertently discussing multiple personality, based on the author's own psychological issues, since I think that over 90% of all fiction writers have this kind of psychology as a key source of their creativity.