Why is a permanent leader important in communism? - eviltoast

I understand the party is in charge and those positions will change but in most socialist states there seems to be a permanent head ala Lenin, Stalin, Castro, the Kim’s etc.

Is this what Marx meant by dictatorship of the proletariat? Is it possible to have democratic communism? I’m new to all this but I’m finding it all really interesting. Sorry if this is a common question.