The games are hidden on steamdeck as well. The steamdeck store homepage ignores the hidden setting when displaying the ‘recently updated’ category (or at least it did a few months ago, haven’t checked in awhile)

Its just the big picture mode of steam, you can still use the Steam client in desktop mode and also have a nice experience on it. But the big picture mode is the default and you can also figure it out on you Windows Steam Big Pic client.