I've just finished this and really loved it, felt it was a return to form after the ink black heart which I still Enjoyed but not my favourite.
Anyway, in this one, strike and Robin are investigating a cult called the United humanitarian church and I did notice a lot of parallels between the church and trans ideology.....
For example
The church has a difficult relationship with the truth
It encourages members to cut themselves off from family members
Its emphasis on the spirit over the body- at one point Robin is chastised when she is undercover as a cult member for referring to someone as gay- she is told "bodies don't matter, spirit matters"
It was brilliant and thought provoking and JKR is a genius.