Valve has confirmed that the Steam Deck's storage options are upgradeable as they come with a 2230 M.2 slot. However, the company, it seems, doesn't want end users to upgrade the storage.
Build 22623.730 (KB5017385)
Windows 11 Preview in Beta Channel comes with Tablet-optimized taskbar
windows 11 insider preview
Windows 11 Dev Channel finally brings Task Manager with a right click, and more
windows 11 promo