I don’t understand this tbh. It’s here already. SteamOS will likely be just like the deck - immutable arch running the existing steam package.
You can totally do this today and it works great. Don’t want to mess with arch and that confusing command line? Use something easier like mint and install the flatpak - then you don’t even have to futz with nvidia drivers. Or use bazzite?
What does steamOS offer that we don’t already have? (Serious question)
This is my thought as well. Why do you believe it was deleted? It’s probably still there, you’re just not booting it. Even easier, pull up your boot menu when you start your computer and see what’s there. I bet you’ll see windows and can select it?
I just can’t imagine Linux doing this. If it’s really gone, I’d seriously question what you did - (did you install to a wrong drive, did you format a partition by mistake, etc?)