Quite honestly, I don't believe either HM or Charles WANT to take the title away from the Sussexes, but from where I sit, it looks like either Harry's HRH (which, thus, means Meghan's, too) has to be given up or the Sussex title given up. Meghan, of course, leaking through friends nasty comments about Britain, the toxic royal environment, her toxic life in Britain, etc., isn't exactly making it easy for the BRF to be accommodating here. She's under no illusion about how they feel about her, but I believe she's counting on how they feel about Harry.
But they also have to factor in public opinion in Britain, which, remember forced them to reverse position on Diana having a state, rather than private funeral, even though she was technically no longer a member of the family.
Meghan's petty and dismissive behaviour has made it more, rather than less, likely that Harry will suffer the loss of one or the other title. Were I the BRF, I would make keeping "Sussex" and using it as their brand only possible if Harry gives up his own HRH and the Sussex title is rendered non-royal. That lessens the image of grasping, conniving Harkles making money off "royal" connections, and makes them pay a price for trying to do by making them, essentially, nonroyal in real terms in Britain.
That move also will preclude any further taxpayer support for them, not just when they become "financially independent" but immediately, which restores at least some semblance of awareness that the taxpayers have lost about 30 million quid on the Sussexes in two years, if you factor in the wedding and its security costs. H&M lose Frogmore Cottage as a "home base" when they are in Britain, and forces the notoriously frugal Charles to fork over enough to cushion his son further as Harry exits.
Anything else will be a disastrous look for the BRF.
That said, I wouldn't count on them allowing that to stop them from letting Harry keep his HRH, his ducal title, access to Frogmore Cottage when in town, and insisting that some "legal agreement" re merchandising the Sussex name mitigates the glaring exercise of royal connections to make lots of money, whilst the taxpayers who shelled out that 30 million on their behalf are left with egg on their faces.
So, R228, I wouldn't put that bridge up for sale quite yet, if I were you.
The BRF has "form" when it comes to behaving really stupidly over bad behaviour amongst their own.
Remember, they are cousins of the Romanovs.