Actual facts, not suppositions.
I just looked up Bower's book. He doesn't even get the name of the foundation Soros set up correctly. He calls it "Open Society", when its actual name is the "Open Society Foundation". If you read carefully, he doesn't say that Soros gave any money to Harry and Meghan but that the Open Society [Foundation] gave money to Colombia and opposition politicians had claimed that the Colombian government was using some of the money provided by "Soros" (as if Soros himself sits there doling money out) to fund Harry and Meghan's trip. Bowers has seen no evidence for any of this himself and his references appear to be from an article written by an opposition politician. But the Open Society [Foundation] doesn't give money to governments for the general budget, it gives money for specific projects, e.g. reconstruction after an earthquake. If the Colombian government did siphon off some money that the Open Society [Foundation] had given for other projects and used it for Harry and Meghan's trip, then that's on the Colombian government, not the Open Society [Foundation], Soros or Harry and Meghan.
https://www.opensocietyfoundations.org/newsroom/open-society-launches-1-5-million-earthquake-rebuilding-fund-in-colombia
It's a big step from allegations against the Colombian government by opposition politicians to "Harry and Meghan are being funded by shady billioinaires with nefarious ulterior motives". But Bowers can (just about) get away with it because he has cited a reference (an opposition politician with her own ulterior motives against the government).
Bowers also claims that the Colombian politician who invited them even asked them to match Soros's (i.e. the OSF's) donation of $400 million! This whole story is more a case of Harry and Meghan being exploited by politicians in a country with politicial problems than anything deeply dubious. Of course King Charles is going to want to make it very well known that they do not represent the royal family in any way!