It won't be Charles. He likes being outspoken on political issues and probably would prefer to keep being outspoken, rather than being constrained by being King.
It probably will be William, though I can see him abdicating just to screw with Harry. Giving him and Meghan that sort of spotlight (as regents for the kids, presumably) when they really don't want it seems like something they might pull after Harry and Meghan tried to leave.
… what in the
Please, just stop posting your thoughts on things. Please. I am literally begging you to stop.