Kings and Queens

I was thinking that the current national anthem of Great Britain, and a few other places, is no longer "God Save the Queen" since the Queen died. It is now "God Save the King". But that thought has me thinking in truly republican terms: since the only real difference between a republic and democracy is that the republic doesn't have nobility.

That means a democratic monarchy can have a hereditary head of state who can be totally out of it, which in the case of Britain was King George III. Republics ...