very rare that I pick up a book and am surprised by asexual characters but I started Vagabonds! by Eloghosa Osunde yesterday and it seems like one of the characters is probably ace in some form:
it's very much an ensemble cast kind of book, and I doubt it'll be explored in any more depth than this, (the character in question has POV chapters as well (she's also a lesbian)
her (kinda magical immaculate conception) daughter also expresses a lack of interest in boys (or girls mostly) at one point, though it could be an age thing
and also the main character in another chapter seems maybe aroace. She's trans too, her narrative is moreso about that
not something explored in depth but still nice to find! and the book is good