My setting has a kingdom whose last king died and their heir went missing; the last king had become a bit of a mad tyrant when they were alive, so the people are in no hurry to have another one. The country is ruled by a Regent’s Council with the elected Regent as a sort of chairperson. Every session of the Council starts with a statement that the King can’t be present and that the council will make decisions in his stead. It’s been so long that the king’s heir, who was a toddler when the king died, would be middle-aged by now, but they’re in no hurry to find him and the heir himself has no intention of coming forward, if he even knows that he’s technically king. They’ve basically become a democratic republic while still being a kingdom on paper - which is deliberate, because there would be political consequences to not being a kingdom any more. For years everyone’s just politely pretended not to notice.