Troubled Blood isn't marketing transphobia save in the mind of a reviewer with an axe to grind wrt Rowling's public statements.
The wikipedia page outlines the charge that it contains "pernicious anti-trans tropes" and continues:
Nick Cohen, writing for The Spectator, argued that the transphobia accusations were baseless and slanderous, noting that Dennis Creed is investigated along with a dozen other suspects.
He also stated that the book does not engage in the politics of women-only spaces and access to gender reassignment treatments.
Alison Flood, writing for The Guardian, expressed similar views, arguing that people who have not read the book were making wrong assumptions based on a single review.
Allan Massie, writing for The Scotsman, stated of the character of Creed that "there is no suggestion that he was transgender".