Not actually interesting, I live in France and am English. You can see fox news 24/7 on youtube if you like. Or you can watch it's baby English brother GB news.
Personally I don't watch any of them and I deleted facebook about 20 years ago but they are the goto reference for older people getting radicalised into conspiracy theories so that's what I said.
As others have noted it is a matter of fact that the Russians and probably other states too have used social media to attack the UK and are probably doing so right now.
It's not a matter of fact that someone is using Harry to 'destabalise' the UK monarchy because it's perfectly clear he's doing it all by himself and if you did want to do that you'd pick someone more dangerous and equally pliable, like Andrew.
There's practically no active republican sentiment in the UK. Plenty of people, myself included think the idea of a hereditary monarchy is absurd but we are where we are and most of the time it works and is no worse than many other countries where the head of state is titular.
Shit stirring by foreign powers with Harry and Meghan is not going to lead to a revolution, an abdication or any other major change just a lot of sighing, tutting and LOL's.