Charles & Camilla - change nothing. Crushing it.
Will & Kate - tricky. Are they still together? Is this a "soft splitting"? Stop with the soft focus Timotei ad stuff, do some actual cancer charity endorsement, and then just allow Kate to fade from view except for 2 - 3 annual engagements.
If they ARE still together she needs to suck it up and get back to work full time when she is better. She had a very very long time to think about whether or not she wanted this job, and nobody gives a damn about big vague projects - people need to see their faces at worthwhile events and charities, picking up the phone to use their influence and been seen to make people's better at a grass roots level. Kate's always been a little bit Boden catalogue and she needs to be more serious now. She's going to be Queen in five years.
If they have split up, they need to continue to phase her out gently and drama free (as they are now, if this is the case) before Charles dies, Will single for 2 - 3 years, phase in Rose. But then they need to start building up Will's reputation independently and with demonstrable hard work, because he is little liked now. Possibly focussed on the military. He looked nice in a uniform, and they should capitalise on that.
Harry & Meghan - move heaven and earth to get them back part time. Give them all the long haul engagements - Africa in particular, and divide the brothers as domestic/international. Meghan willl have fun, not have to live in England much, Harry seems to like that kind of thing anyway. Prise them away from the US before they make it worse.
Yorks - get Andrew out of that house, and make it Harry & Meghan's British residence as they need the status more than he does. Retire Andrew to Scotland (sorry Scotland) and get him firmly remarried to Sarah to dispel skeevy image and promote their happy marriage, but no royal engagements or work. Allow Beatrice & Eugenie to just do themselves as they see fit. They're doing absolutely fine, unless they want to get involved, which they probably don't anyway.
Anne - let the woman retire.