Responses
Actually, Diana and her trainer(the former royal palace head maid/nanny) had a falling out, and she left the palace to retire early. Diana was stubborn about getting her way, even messing up tea parties to make it religious. She even brought temple people into the palace to be her people.
I agree that Diana doesn't have the best reputation in Kael's mansion due to her choices and how she treated Hestia as if she's the enemy.
He's can't be paid enough to deal with this. Though everyone in the mansion also shares Hestia's thoughts.
This made me feel bad for Diana, she seemed to have no real help into settling into her role. What help she did have she sent them away. Helios thought she's just be good at it naturally, in love with her Saint persona. Diana was blinded by the shiny palace life and didn't realize it was a job.
That why people who marry royals get training and secretaries. It's a job, it's always been a job. Even if you want to live quietly you have to do it in a way that doesn't upset other people. This also applies to lottery winners, a lot of people lack the mindset to deal with sudden change.