Congress is elected by and serve at the pleasure of the American people.
Public servants in Executive agencies are appointed at the pleasure of the President and his Cabinet as applicable, with some appointments requiring Senate confirmation.
It is therefore "removing democracy" to task unelected public servants with writing laws and regulations. The task of legislating is the duty of the legislature, Congress. The Executive Branch's job is to execute the laws as legislated by Congress, hence their name.
>Logistically, how many laws would Congress have to pass each year to have a functional society just to keep up with research and industry developments?
More than now but less than what would be humanly impossible. Make those fucking Congresscritters earn their pay and votes.