Sophie (and to some extent Anne, though as the only daughter of the Queen she might be given more free ways) is my answer to all those: ...but she couldn't overshadow … and was therefore told not to work more.
This was used by Margreth who (according to the new gospel "the Crown"
) was depressingly bored, longed something meaningful to do and was told no by the Crown, as this would take away from the Glamour reserved to the Queen and Lady Di.
It was used by the Kate and Will supporters to explain their lack of work, since they could not be seen working more or more efficiently than Camilla and Chuck...
And of course this was used by Meghan and Harry.
Yet, looking at Sophie's endless, efficient but rarely headline-making work, all of that has been bullshit.
So basically in the above mentioned cases 1 and 3: it wasn't about work to do good or to combat boredom, but to gain limelight and headlines and do the fun stuff.
Because as I can personally attest: charities forever need hands to do the gritty, and never ever does the press cover me instead of the head honchos.