Though from what I've read, Microsoft could fix that relatively quickly, if they made some tweaks to Windows (and called it a special 'handheld gaming edition' or so).

For some reason, the Lenovo Legion S's Windows still comes with a lot of baggage and background services etc.

If LTT is to be believed, this is in the works Maybe SteamOS managed to ruffle enough feathers to start moving the inertial colossus that is Microsoft, not that I have much trust on their willingness to leave a good idea remain good in the long term

Microsoft is a big expensive oil tanker. They have the resources to turn the ship around, but they need to feel incentivize to do so. I love using Linux and won't go back to Windows, (it's been quite a while for me) but they could blow the performance problems out of the water if they really cared to.

It's called Xbox Full-Screen Experience and is marketed as Xbox PC.

It's available now, but nobody's been impressed yet. Gives you a gamepad-compatible launcher (although the gamepad PIN to login is buggy). Doesn't seem to actually save resources.

I might have to look into this for my ROG Ally X... it already runs pretty beastily but I'm never going to complain about better performance...

Edit: though, I'd have to give up my Fallout 4 with mods. (Don't judge me I know it sucks but it makes the dopamine go brrr)

FYI, you can install Vortex on Linux systems and mod games via that just fine: https://github.com/pikdum/steam-deck/

(Edit: their native version appears to be in-development, but doesn't currently support non-native titles: https://nexus-mods.github.io/NexusMods.App/ )