You seem to mistake an ideal for reality and forgo a few difficult eventualities: eg. tyranny of the majority, corruption, regulatory capture, etc.

Depends on the specific incarnation of the democracy. Not infrequently in elections the majority sees the choice as the one of the lesser evil.

The state might be comprised of people, but unless everybody is directly involved in the final decision process you'll always have (at least) a principal-agent problem between the people acting as political representatives and everybody else.

As you do in most things in life.

Do you grow your own food? Do you refine your own oil? Do you write your own contracts?

I would assume you pick somebody to do those things for you because one human can't do literally everything.

"Democracy" is just a word. It means rule bu the mob, and adds no other details. Describe what you mean by it.