I think Harry will still keep his links with Invictus (which was not a role bestowed on him by the Queen) and I think he enjoys that. Whilst he is not a working Royal, he is still a member of that family and is still very much a part of that family.
I do not think he has let the Queen or his country down (although he might have managed the announcements better). Ultimately, he has gone from 3rd in line to 6th in line. His role (and I think he has always stuggled to find a role since he was never brought up to be King) has diminished as William's family has expanded. Given what he saw his mother go through, I can understand that he might want to try and control the media or face it on his terms.
I read the recent judgement on the Duchess's case and it is clear that the DM went far too far. Unfortunately, she has trailer trash family who have been stupid in giving the press too much access and have allowed themselves to be completely manipulated by gutter press reporting.
I do not know her personally, but I haven't warmed to her. Having said that, I really do have a lot of sympathy for her. If the Duchess of Cambridge did something she was generally praised in the press; whereas for something similar the Duchess of Sussex was hounded. She could never win.
As for the upcoming interview, Charles did it, Diana did it, Andrew did it (all with pretty horrendous results). So I do not see it is so awful that Meghan and Harry are doing it.
I hope they can find some happiness.