The deep state is anyone/everyone in the government for longer than ten years.
One such organization is the Bilderburger Group. That is not a fictional organization.
I agree with your statement of “The deep state is anyone/everyone in the government for longer than ten years.” It is also the bureaucracy that has become entrenched and especially those partisan political appointees who managed to become civil servants, but still believe in their allegiance to the politician/party that appointed them, rather than being neutral to the party in power now that the are “civil servants.”