I would not want to be anyone else because it’s hard enough trying to figure out who you want to be.
I think most humans spend too much time thinking about what other people are thinking.
You may think it would be cool to be a famous millionaire for a day until you start thinking about what that person’s day-to-day routine may be and how that person became so successful. Many uber-successful people (“successful” in the typical way measured by financial wealth) are also very obsessive with a palette of mental issues with which they deal have to manage every day. If you could step into the mind of any person for a day, you would need to deal with the negatives as well as the positives.
Instead of fixating on another person’s life, focus on your own life, and take actions to improve it. Every person has their own circumstances of life to manage.