Try it. Move your Steam window around. See how it snaps to the edges of your display(s)?
Why is Steam the only program (I know) that does that natively? I would love for ALL my Windows programs to do that (without installing 3rd party softwares/scripting).
EDIT : I’m on Win10.
Windows key + left or right arrow key will blow your mind.
That doesn’t really help in my experience because this state is not saved. You have to do tricks in order to get it saved like move the window a bit or resize it etc.
Check out PowerToys
I know this shortcut, and it resizes the window to half-screen. Got any shortcut that does the same, without resizing?
Check out Multitasking settings and see if any of those do what you are asking.
IIRC, Windows key and Up arrow will maximize it. Not aware of a way to snap a window to the top without it changing size. Would be pretty cool.
You might want to check out Windows PowerToys and specifically Fancy Zones. You can create your own areas to snap windows into. Still not quite what you’re looking for but might provide an alternative approach.
Also up and down after left right