As my formidable undergrad professor, Dr. Nina Auerbach ob"m, used to say: Every gothic novel can be condensed into a three word summary. Girl meets House.
It's true.

I was absolutely here for this book as soon as someone mentioned Rebecca because I have a complicated and messy relationship with the gothic novel - itself a complicated and messy genre. It's my favorite form of...not precisely horror but something related to it. And what Khan does here with her haunted house that has also kind of become a haunted apartment building with a somewhat absurd supporting cast creates a novel that successfully lives as a genre intersection and those are not easy.
Khan also really gets that the gothic is the genre of self-and-other and that the axis along which "other" moves is - to some degree - always about who is not merely other but Outside. (In that respect it's a genre that can only exist in an era of Empire even when imperialism is not explicitly the topic the way it is here and in Jane Eyre.)
This book is also super interesting because, as with any book in the shadow of Edward Rochester and Max De Winter,

the question of how you portray the master of the house is going to be crucial. Is he a good man? How does a good man come to own a gothic house? Is his goodness real or in his own estimation? Is it ever possible for the owner of a gothic house to be a good man? I think this book comes the closest to successfully answering that question yes (assuming you say either that setting him on fire in order to reform him is beyond the pale OR that Rochester is not fundamentally a better person at the end of the book, he just has fewer resources with which to be a dick). In doing so, Khan gets gorgeously into the role that privileged women play in oppression across race and class lines and the degree to which the men who "transgress" societal norms are hauled back into line by the hurt and pain caused to those they love because they are not themselves touchable. It's complicated and she does a good job making her characters sympathetic without asking us not to judge them.

If this doesn't sound like a 3.5 star review, you are correct and my main critique is that I finished the book and still have no idea why the djinn needed to be a part of the story.