I worked for an IT company that had me traveling weekly. If I wasn’t traveling to a location in the US, it was to an overseas location, where I stayed for a year or more.
My company, understanding that those who traveled were giving up a great deal of their life, gave us the perk of flying in first class.
I find domestic flights in first class to be pretty normal. They food isn’t a great deal better.
It also depends very much on the airline. I flew Air Emirates several times and they are great. My seat is always very private, with both doors closing to give me my own small room (more like a capsule). The food is excellent. My seats were something like this.(photo). There’s a partition that comes up to separate me from the seat next to me. In the evening, the flight attendants come to make up your bed. Your seat flattens into a somewhat comfortable bed. With sheets, pillows and blankets, it’s pretty great.