I think the senior Royal life model bored her to death. She’d have been better as a Zara/Mike participant. There for the fun and glam stuff but not having to commit to all the formal events.
There’s a lot of sitting, listening, smiling, sitting though church services and memorials. Lots of time between needing to be filled with appropriate activities.
If you have a rich inner life and lots of hobbies and activities you can thrive.
Sophie pouring over the military archives for example.
Kate doing all her sporty stuff, plus drawing, painting, playing the piano etc.
You need to keep busy in those environments otherwise you’d end up non stop doom scrolling on the DM comments section and getting into your own paranoid head about what everyone was saying about you.