There's no denying Trump definitely had the most energy and worked the hardest of any President in history while in office.
Not only was he running the US, he was also leaking to the press, making deals for his businesses, getting into fights with reporters, calling into Fox News morning shows whenever he felt like it, trying to beat the FBI at their spy games, campaigning 24/7, hosting parties, winning government contracts, meet with Rudy's friends, blackmailing Republicans, evading lawsuits, breaking fundraising records, flying all over the place and tweeting all day while still somehow finding time to be up to speed on the latest gossip, world events as well as whatever drama was playing out either on the 24/7 news channels, among his staff or on the internet or the world in general and respond before the 'US Government' officially could.
Most companies need a staff of 10 dedicated marketing and PR workers to write and push that many messages to their audience and stay in the loop.
Meanwhile Trump did most of it making a point out of not utilizing the vast resources of the US federal government because they were losers.
Commanders and generals in charge of complicated military operations in Iraq, Afghanistan and other places like Kelly could by their own account not keep up, understand or keep track of everything he was doing.