Could she just say "no" to Boris' request?
I know she has always taken the advice of her PM and has never commented on politics - but, this PM is not elected, has only had one day in Parliament while it was open and is causing a constitutional crisis. I can't imagine she is enjoying working with Boris (and Trump) after working with some brilliant minds over the decades.
Added bonus - would stop us all from paying attention to Prince Andrew.
I'd be seriously tempted, if I was Betty.