I think this was MM’s plan all along with the relocation.
She’s very happy to drop PH and the kids in the UK to accumulate Britshness and Royal glitter which she can then merch post divorce in the US for the rest of her life. She’s even doing that now with her latest Tweedy Cotswolds As Ever shtick.
It would suit her for PH and the DCs to be doing faux royal stuff maybe even RF public stuff (Sandringham walk, garden parties, Christmas concerts, Ascot, Trooping etc) - in time before anyone bites my head off. She’s savvy enough to realise that this won’t happen with her on the scene so she’s happy to step back from that stuff if her absence makes it happen and ultimately lines her own pockets.
Their first relocation announcement centred on MM needing to work from their international bases - ie don’t expect to see her too much as she’s fading her broke, volatile, shabby, addict STBXH out - attempting to ensconce him safely into the arms of his community, country, family and friends because she’s done with the fool - but she still needs to rinse his residual legacy value however little it may be by being a Prince. Same with her DCs she needs them with the specific aesthetic British accent, boarding school, hunting, shooting, fishing look to flog on.
She’s always looking at the next rung / neck to stand on. I think the TMs crisis will just expedite this process and a bit like the 2019 letter somehow provide her with in her eyes the perfect excuse to publicly dump her STBXH (he didn’t support me in 2019 - he silenced me and made me bury it and go to the Royal Albert Hall - he didn’t support me when this then blew up etc etc.
Shes on her way out of that marriage - shes happy to leave PH and DCs behind if it serves her goals.