I feel like "form your own private paramilitary organisation with minimal oversight, then expand their reach by having them take over the operations of other government departments" has been done before somewhere, as part of a larger plan.

They dont have all the skills to do anything super complex in a sustainable way. Already proved in the first term. What their existence demonstrates is winning election is not super complex if you can find enough groups to precisely target and pander/capture attention. Social media has been a force multiplier for such behavior and the people that have emerged dont have any other skill other than attention capture. But thats short term win like full focus on marketing while product and operations have no hope of catching up. Every "large plan" will fail. Large plans in complex ever changing environments always need massive cooperation of very different skills. Never happens sustainably with just one skill dominating all.