Source is this video:
Windows Was The Problem All Along - Dave2D
We could obviously compare performance between windows and steamOS before on the steam deck, or between windows and Bazzite on other handhelds. But this is the first time we have had official windows and SteamOS builds for the same hardware.
Arch is a stripped down version of Arch.
Linux isn’t monolithic like Windows, so it can be purpose built for anything.
Windows LTSC is designed for things like kiosks, ATMs, etc that have a long service life. It’s not made for gaming. It doesn’t even include things like DirectX by default, IIRC. You have to add it.