Steam could alleviate storage issues the Steam Deck may have by allowing for a back up sync system with other devices on a home network.

What I mean by this is, Steam should make an app for a NAS, be it Synology, QNAP or DIY NAS solution. Or alternatively, a feature for a home PC to allow for quick data sharing of verified install files.

This could work in two ways, the first being the most simplest.

1) Your NAS (or PC) has logged into Steam and has either an 'Install' or 'Back up' of a game on its storage. Your Steam Deck (or another PC) detects this NAS (or PC) on the network and will seek the required game files from the NAS automatically before going online. Therefore this allows for very rapid install / uninstall between games with the bulk of the data being stored on the NAS / PC. This also is an ideal solution for households with or without a NAS, but would like to have an easy method of shared game install between PC's (which you can do manually anyway).

This method doesn't even need to be that clever or require an app on the NAS. For instance a USB HDD plugged into a modem acting a make shift server for a home network. If the Steam Deck installs a game, it would be nice for the Steam Deck to designate a backup location and have an easy feature of creating a self updating back up at that location. Whenever the game gets an update on the Steam Deck it will then proceed to update that back up. That way should the user run out of space on their Steam Deck, they can uninstall that game. Install their new game and at a later date when the user goes to re-install the game Steam will just pull the files off the network storage.

2) I've heard of people trying to run games where the files relied upon are being pulled directly from the NAS in real time. While do-able WiFi probably isn't at the stage where this is practical. I hope this is a future plan.