Renaissance Technologies is one of the few places where you'll see billionaire engineers and scientists in the world of Wall Street. Due to the nature of how they capture returns in their primary fund (it's now for insiders only, so their outsized returns go to the employees with a stake).

https://en.wikipedia.org/wiki/Renaissance_Technologies

Yeah, there’s them. But there’s other ten man funds that can generate massive returns.

Depends on the role, but usually for software engineers one requirement is to pass an algorithms interview. so being really good at leet code. people have told me they did at least 600 leet code questions just for that specific portion of the interview

Some of them, possibly the most successful, are reputed to hire pretty much exclusively people with non-financial backgrounds - mathematicians and physicists who are also really good programmers.