There have been various tell-all threats in the past. Including Diana's famous interview.
Also, if I remember correctly, there have been threats by some intimately connected with the royal family. I believe Paul Burrell has hinted that he could tell some stuff if he wanted.
I don't know what deal will be struck between the two sides, but one will. And then the tabloids (especially The Daily Mail) will spin the story in favour of the queen, and tell the country that a palatable agreement has been reached. Harry and Meghan will carry on with whatever roles they are left with and become a celebrity couple in the US, and the Royal family will carry on as normal.
At least until the Queen dies. Which really can't be too far in the future.
If they leave the papers will say that the queen is heartbroken and did everything she could to stop them leaving.
If they stay in a limited role the papers will say that the queen worked hard to bring the two sides together.
We will never know what really happened.
l was never a fan of the Monarchy and l for one, would never have married into a family such as they are. They are a business and seem to be run like a business and any emotions are tossed to the side in keeping with traditions and duties. The Royal Family could bad mouth Diana all they liked because it was her against the whole lot of that family and she knew she was not going to win, but at least she opened the door for some very dirty unaired truths about how she was treated and talked to while she lived at the Palace (including the men in grey) she talked about being around every corner watching her and listening to her.
As you stated, no one will ever know the truth, but listen up now, Meghan was hated, beyond hated and had to go through that on her own and the Palace never did stick up for her l noticed. l also saw a similarity between her and Diana, they both needed help, asked for it and were refused...Both of them were in essence in the same boat and Diana died in a car, so what is this Royal Family of Murderers going to do next? Harry and Megan suddenly have an accident and die as well?? Can't have those accidents keep happening as you know, people are already judging the value of this Royal Family and what is the actual need for them. There isn't one. Kick them all out and get rid of the Monarchy and let these people live off their own god damned money and leave the taxpayers alone with their money. They are like disgusting bottomfeeders, looking to make new money in some new scheme. They are an absolute embarrassment to the rest of the world...Diana opened that door for Meghan to carry on bringing light into that dark abyss of a family who are not rightfully related to the real Holder of the Throne and Diana proved everything Megan had to say. The Royals are all racists because if you don't have the money or the title, you are nothing to them but something to hunt and eat.