The freedom he has is to make sure he can decide on the future of the world, that's what his money bought. Not everyone is same as you said, some play computer games, some drink expensive champagne on a yacht, and this is why I believe that we are going to end up with a lot of difference between people. But, the reason why Elon just tweets and plays pc games when he has the time, is because when he is working, he is working towards changing a whole nation, not even a nation he is from, not even a nation he grew up, not even a nation where he started his first business, a nation that he went when he was already a grown man, only because it's the most powerful nation in the world.
So, with his 400+ billion dollars, he is earning himself influence over the biggest nation in the world, his goal is to make sure that he can do something to that nation, and put his name in history. When you are that rich, they let you have a government branch, and D.O.G.E. is a branch Elon will control, so you have to accept that money did helped him a lot.
Yeah you are right, I believe that having the benefit of going against everything a government stands for requires a lot of money and his 400+ billion works for that. He is not a nice person and I never liked him and I believe that him being in any position of power will be terrible for the world, but at the same time we need to remember that he is just some rich dude who wants more. All that diablo being ranked at leaderboard stuff? That's literally what he is seeing with money as well, he is using Forbes richest list as a leaderboard and he wants to be richer than everyone else, that's all he cares about.
I think with this much power, and influence, over a whole nation, he might have reached where he wants to, this could be his end game, don't think he can do anything more than what he is going to do this four years.