This section is interesting:
"I think for subtle, different reasons. I think she always thinks she knows best. I think that she's clearly a smart individual. She's also one of these people who thinks she's the smartest person in the room which is a mistake, however smart you are.
"Harry is slightly different. He thinks the world is against them, or large portions of it are, and therefore dismisses a lot of what people have to say on those grounds.
"He would never do anything because the media said he should, that would be the last thing he would do."
I have read Courtiers and it was fascinating, less for the Sussex saga as for an insight into how the palace works in general. It's so disjointed I don't think any conspiracy has a chance of working.
I think Low nails the dynamic here. Neither of them can take advice, for different reasons, and together they don't help each but just double down on their own decisions. Which would be fine if they made good decisions.