I would say that Harry & Meghan have totally got that message. Harry himself said no-one wants the top job.
I think there's big differences between Charles and Andrew & William and Harry; who have always been close.
Andrew is 12 years younger and Charles would have been heading to Gordonstoun when Andrew was a baby.
Even Charles and Anne who are very close in age are rarely seen together.
I think Harry & Meghan will be just fine taking care of the Commonwealth that is a huge undertaking anyway.
I think as a foursome the Cambridges and Sussexes will be mutually supportive. From her approach (low key fashion, under the radar projects) as we see more of Meghan, I do genuinely think she is not seeking the limelight, but she has the skills to be able to cope with it as part of her Job.