I was working in a government office, a teaching and research institution, before retirement in 1996. My boss used to be present in the office 14 hours a day, including "weekends". He was driven to office and back in a staff car, by the staff driver. (His residence, provided by the office, was ten-minutes walk from the office.) He liked the office, because he had two air-conditioners for his room; it had two sets of large couches, ostensibly meant for receiving important visitors; the staff car along with driver was at his service all the time; so was his personal attendant, a peon; sometimes he would detain his secretary also. More than anything else, his wife liked the idea of having him out of the house for as long as possible.
The trick is to make it look like you are busy, even when you aren't. Most bosses don't know how to tell the difference and it frees up a lot of your own time. For example, if a boss talks to you, act like they are distracting you and you just lost your concentration, even if you didn't. That's how to free up time to not be constantly busy and yet seem busy at the same time.
Also it's never about freeing up time, bosses like that often think you should be working 100% of the time you are paid for, so it's about how much "more" you are able to do. "I set-up a new system that makes me around 20% more productive", just done, don't use the word time, because it'll make the boss think you are using company for your own time.