Apple designs their laptops to throttle power when they warm up too much. Framework gives theirs a fan.

It's a design choice.

Also, different Linux distros/DEs prioritize different things. Generally they prioritize performance over battery life.

That being said, I find Debian GNOME to be the best on battery life. I get 6 hours on an MSI laptop that has an 11th gen Intel processor and a battery with only 70% capacity left. It also stays cool most of the time (except gaming while being plugged in) but it does have a fan...