This article does a good job of talking about how poor the windows experience on a handheld is, and why SteamOS could dominate handheld devices if windows doesn’t start to make serious changes to improve it’s useability and performance.
To be clear, I don’t want to see windows succeed here, I would absolutely love to see SteamOS take over the handheld space and be a real linux ambassador to show people that they do have other choices than windows for their computers.
No, right now it only works on the steam deck. Support for more handhelds is coming though, and eventually laptops.
Right now you can install Bazzite to a laptop, it’s very similar to steamOS and will work on most everything.