"Good battery life" is not my measure of good power management. I can leave my windows laptop sitting out, it will sensibly turn off the screen and eventually hibernate, I don't need to worry about it. A Linux laptop will need babying when it's not plugged in.
Gnome has power management features like that, didn't even enable them. It's the most installed DE I think, so your characterization of Linux is pretty off.
I like Gnome and its newest incarnation Gnome 40, but at least on Nixos it has some issues so I often rebuild to an i3-based environment instead.