This so-called "deep state" never assassinated a single foreign leader. Not one.
Did they try? Yes but they - the CIA - were ordered or directed to do so by presidents. Castro most notably. Eisenhower reportedly approved a plan to assassinate Lumumba but the plan was not carried out and he was murdered by others.
I'm not going to defend the truly awful things done by the CIA during the Cold War. But almost all of it was done under directions by the president or with their knowledge. This wasn't a "rogue agency" acting on its own. And to argue from "the CIA tried to kill Castro therefore they killed JFK" is such a reach that it's remarkable that anyone tries to make it. Killing a foreign dictator is completely different than killing your own leader. That should be obvious.
The CIA in the era of Dulles and Helms almost certainly went rogue a number of times. I'll grant you that the CIA today is more bureaucratic and less inclined to "go rogue" than in the 50s and 60s but there are reasons to think that some employees at the CIA went rogue against President Trump.
President Truman disagreed that the CIA wasn't a rogue agency and called for them to be reined in after JFK was killed.
President Eisenhower warned about the Military Industrial Complex
President Reagan I believe really had no idea what was going on during Iran-Contra. His VP, George HW Bush, likely knew more about Iran-Contra because he had a more intimate relationship with the CIA.
I would define the "Deep State" as a combination of High-Ranking NatSec people, Defense Industry people, some members of the Press, and wealthy oligarchs like Rupert Murdoch and George Soros for example.
To me, the 'Deep State' is just a group of unelected elites who are able to manipulate and influence policy decisions related to national security and foreign policy without being held accountable. I do believe that sort of Power Elite exists within the US and began sometime in the early 20th century (predating the creation of the CIA).