They have separate kitchens for the prep, the cleaners work while they’re out on the yacht, they have people to do the buying, and the restaurants they visit have very well trained staff who stay out of the way.
First is you get a particular group of people to work for you. You tell them they are better than all the other poor people out there, that is get them to be nationalistic/racist, etc. You also give them a little bit more than the abjectly poor so they have something they fear to lose. You also let them know if they upset the situation they are in retribution will be swift and brutal and affect anyone they know and love.
The vast majority of rich people don't get murdered.
Those that do, yes, usually get murdered by those in position to do that (i.e. those that have physical access to them). That's neither interesting nor relevant though.