Yeah I know no account is 100% reliable and free of agenda, but pretty much all the many — and there are so many — separate non-anonymous household insider accounts confirm a hellish divide between public and private persona/behaviour.
I haven't watched The Crown but I've heard S5 came under flak for portraying her maliciously as unpredictable and manipulative, but the author has said it's based on source material provided by Diana and Charles (interviews, audio tapes, biographies they willingly contributed to), themselves, no secondary material. It's also quite dialled down.
This may rub some the wrong way but to me as someone familiar with personality disorders, even her tragic accident was no different to how many PD women with impulse control/paranoia die young. Her own former protection officer said that she'd be alive today if she hadn't dismissed her royal protection officers, who wouldn't have treated escaping from the media as a life-or-death emergency.
She also had a similar kind of twisted relationship / doomed dance with the media as Harry did. She hated the media with a passion, but would often collude with them to create a public narrative and get back at Charles and RF. Big name (again non anonymous) editors recount how she would call in with juicy details and tip offs about herself.
I say the above without judgment, only sympathy and interest... She had an awful childhood though I feel sorrier for Charles.
Also, yeah maybe meant to be mischevious bullingdon club/schoolboy type talk intertwined with boarding school trauma confessional, I can see an audience for that in the UK... after all no US politician would've gotten away with having a million children, shagging pigs, being caught groping on camera and then appearing half naked on reality TV to sell a woe is me trauma story, etc.
But obviously that doesn't work in the US which is traditionally quite Puritan, even in modern left wing circles.