I have had similar experiences, however, it's important to be specific: the NMCI contract ended in 2010 and DoN moved to the Continuity of Services Contract where we bought services piecemeal until we could fully take it over. The Navy and Marine Corps tried to transition to NGEN during this time but mostly failed and each service ended up taking different paths. Now, the two services operate their networks differently: the Marine Corps, for example, runs it as a government owned and "shared operations" model where it's mixed government and contractor.
I imagine that the laptop you were given in 2018 was not an NMCI laptop, but instead a laptop from either the Navy or Marine Corps' new ownership/operations model which is incredibly flawed. Also, HBSS was poorly implemented in the 2010 time frame and Tanium was introduced (at least in the Marine Corps networks) around 2017. Both are major contributing factors to the issue you're describing.
In short: the current state is that computers are barely usable and that is not NMCI from yester-year.
I imagine that the laptop you were given in 2018 was not an NMCI laptop, but instead a laptop from either the Navy or Marine Corps' new ownership/operations model which is incredibly flawed. Also, HBSS was poorly implemented in the 2010 time frame and Tanium was introduced (at least in the Marine Corps networks) around 2017. Both are major contributing factors to the issue you're describing.
In short: the current state is that computers are barely usable and that is not NMCI from yester-year.