As a person in tech, I have met many millionaires and a few billionaires, and it is really true that huge wealth does not in, and of itself, bring happiness. They're basically still stuck with their old problems, but now also surrounded by sycophants and leaches.
However "Post Adventure/Mission Depression" is very common.
See e.g. https://worldextrememedicine.com/app/uploads/2022/07/Lukas-H...
As a person in tech, I have met many millionaires and a few billionaires, and it is really true that huge wealth does not in, and of itself, bring happiness. They're basically still stuck with their old problems, but now also surrounded by sycophants and leaches.