A Necrocracy if we want to be pedantic. As the highest title in government 최고령도자 (literally translating as “supreme leader” or “the best/most leader”, but can be taken to mean something like “the leader who is in the highest position”), officially it is in charge of the party, state, and millitary, and so far been only given to former leaders upon their deaths. Meaning that at any given time, the highest leadership position is held by someone who is dead, making it a Necrocracy, rule by the dead.

A theocracy would imply some form of church like structure deciding policy, laws, and running the state, maybe you could argue the party is a sort of church, but the party apparatus is not appointing the leader, nor does it set policy. The party, state, and army in North Korea serve at the behest of the hereditary leaders, so practically it’s more of a monarchy.

It's kind of it's own category. I mean, they're basically forced to worship the supreme leader, but I don't think that's a defining aspect

It's more a totalitarian state. Everything from what job you'll do for the rest of your life to how you cheer is given to you by the government.

It has the trappings of religion, but do people really believe that? The way they talk about it is like "the state tells us Kim was born in a flash of light on the top of a mountain", they don't engage with the talking points, they repeat them exactly

"Nah bro, it's a Democracy. It's called the Democratic People's Republic of Korea bro." Yeah, and Nazi stood for National Socialists.