Power is a narcotic that mesmerizes with each dizzying dose. When a king surveys a flat expanse in all directions from horizon to horizon seeing the most destructive weapons ever conceived he must temper the intoxicating exhilaration of all this deadly force at his command with the historical responsibility of ensuring the survival of democracy. Having absolute control over the most powerful military in the universe does not mean this king who is not merely a figure head will use it to bring to heel a troublesome parliament. Abandoning the tradition of absolute freedom in a democracy that has endured for many eons just for a spurt of personal emotional pleasure would ultimately lead to the king becoming a historical pariah. Aside from the negative legacy that a rouge king would bring upon himself the sheer weight of a flourishing, decent, equitable, just, caring society pretty well guarantees that any royal from this culture would never even contemplate ceasing power from the people.
You may have the power to lay waste to a good part of the universe so that many hundreds of trillions of slaves bow at your feet but this only insures that these former citizens turned peons will hate you with every fiber of their being. Posterity, creating and leaving the world better off than when you arrived, this is the drug of choice because it will not leave you morally vacant, despised, and lonely beyond comprehension.
Working within the confines of a democratic system is very painful especially when you have so much power at your fingertips. Frustrating does not even begin to describe all the machinations of billions of legislators all with their own personal, political, territorial, and ethnic agendas. Liberty practiced daily is a messy business. There is absolutely nothing easy corralling all the competing interests into something approaching a consensus that improves the kingdom.
Having a Prime Minister shoulder the bulk of this responsibility helps distribute the necessity of advancing progressive change in the most chaotic governmental system that is democracy. Possibly having someone like a Prime Minister also makes the task of leading easier because not every single detail needs to be crushing down on a single individual? Share this cruel duty.
At the end of the day you need to be at peace with yourself. Respect that is earned will flow in from all quarters if you do your job well. This along with building upon your legacy of accomplishment will carry you towards a more tranquil state. Save your aggressive leadership traits for when they are most needed during a period of emergency like a war with a deadly foe. That is when the warrior spirit, the punishing blow of your power will be blessed by all the citizenry.
Feel privileged to be exulted to such a high position among your fellow citizens.