There *are* a few humans who don't need more than 4 hours of sleep. In my years of software development, I've known just one. He'd go to sleep about the same time as us 'normies', but be up and doing 4 hours later, learning something new, writing code, whatever. No signs I could see of being sleep deprived (in that field it's pretty common). Just a single person.
This was some decades ago. At the time I wondered whether he'd experience long term health effects (like the famously short sleepers Ronald Reagan and Margaret Thatcher), but we're no longer in touch.
Just a bit of anecdata...