employ a steam engine to crack a nut
To use excessive, overcomplicated, or extravagant means or force to accomplish something relatively minor or simple. With this new system of issuing licenses, the government has employed a steam engine to crack a nut: four separate departments now handle each stage of an application, when a single department could easily process applications from start to finish.
engine room
The main source of talent, power, or ability in a team or group, likened to the room that houses a ship's engine. Sarah is our engine room, so with her injured, I'm not sure how we'll be able to win on Saturday.