Maybe Denville is onto something that it was in the run up to the Engagement. Don't really know. I do believe that Harry wanted protection for Meghan but was told that would ONLY happen once they were officially Engaged.
Harry could have paid for protection privately, if he wanted to. That's on him that he didn't.
I also have read that multi millionaire Harry was considered cheap. It was recounted in some Harry Biography that one of Cressida Bonas dissatisfactions with Harry was his cheapness. Didnt take her out much, and He expected her to pay for an expensive plane ticket to accompany him to his friend Guy Pelly's Jamaican Wedding. She didn't rely on her Parents to support her and wasn't making much in her acting jobs either. So it contributed to their breakup allegedly.
Money, money, money seems to be a reoccurring theme with the Sussex's and the Firm. Apparently from the get go, it seems.
In hindsight, it just seems that for whatever AND many reasons, The Sussex's were NEVER going to be able to join in as reliable committed Team Members, to me anyway. It just wasn't in the Cards. I think William recognized that from the very beginning.
Personally, I'm glad it ended so early on. Married in May 2018 and notified the Family-Firm in Dec 2019 they wanted HI-.HO. Had they stayed even a year longer, I fear the breakup would have been even worse.