One thing that perplexes me is why is Harry targeting his father and not his grandmother, the agreements and efforts happened on her watch.
I suspect that it was suggested to Harry that he return to the UK, not because "they" were trying to control him or bring him back into the fold, rather that all this was happening when the planet was headed towards lockdown. If I am piecing things together correctly, the UK removed security and Canada also refused to provide security to the Sussexes at / around the same time many countries were implementing Covid safety measures. It looks like the Sussexes chose to take Tyler Perry up on his offer to house them in California.
Unless it suits his agenda, Harry refuses to acknowledge that the Sandringham Summit was put together hastily in response to the Sussexes releasing their intent to step back via the website. Yeah the statement was that they were forced to release it because information about their intent was reported in the media, I don't agree that they were forced. Anyhoo, the Sandringham Summit ended with loose strings, with security arrangements being the biggest.
The information that was released as part of the appeal proceedings,* indicate to me that a valiant effort was made by the late Queen herself and those working on her behalf to convince the decision makers to keep the Sussexes security in place. Again, I don't know what Charles was expected to do as Prince of Wales and later monarch that had not already been unsuccessfully attempted..oh wait, I can think of something, Charles could pay out of his own pocket, Harry's security costs, I can't remember the term used but it implied that the costs were prohibitive.
Another thing that pops up that is part of this stew is that in Spare (IIRC), Meghan asked Harry about security and his reply was that there was no way they were going to lose their security as Prince Andrew's had not been removed. That was a huge miscalculation by Harry.
* Big thanks to
@Tatiana Maria for all the information provided.