Often think along these lines. Monarchies are based on challenges to the previous incumbents and bloodshed and currently established royal families around the world are lucky to live in (generally) peaceful times. I’m not advocating violence so as not to break the subs rules, just posing a theoretical- say the guy who was hanging about with his crossbow who was allegedly trying to kill the queen, if he had succeeded, why wouldn’t he be the legitimate ruler of the Uk? Not being funny, but why is it any different from the challenges to monarchies throughout huge swathes of human history? Often lineage claims are at the root of it, but what matter is that if he succeeded?