When Donnie first started using the phrase, "deep state", he used it to imply not just the establishment politicians but this supposed secretive, conspiratorial shadow government that nobody else knew about or wanted to talk about.
Many of his (less intelligent) followers believed or at least pretended that he had somehow uncovered all of this himself, and was fighting the "good fight". It was just another catchphrase lie that elevated his perceived character for them.
It was all bullshit, of course.
There is in fact, something to it. There is a level of money and power brokers that decide things for us. They decide who we vote for, simply by deciding who to support and finance. And it probably isn't any of the names bandied about, Koch, Soros, Gates, Bezos, Murdoch, etc. It's the old money people that most people don't know. The people behind the oil companies, investment and acquisition firms, defense contractors and so on and not all from any one country. They are the people guys like McConnell play up to. They are the people pulling the strings of events like Davos.
Call me nuts if you will, but groups like The Skull and Bones, Masons, (many we've never heard of), etc. don't have secret meetings for nothing.
There IS an underground whether you care to accept it or not.