Deck is useless without internet.

[itchiebutt]

So, i don't know if it's just my Deck but when I use it offline it just becomes a $400 paperweight. Outside of being able to play videos.
What happens is the trackpads in Desktop mode love to stop working without internet. The trackpad only works when Steam is loaded. If you close out of Steam or it doesn't load the trackpads don't do anything.
Games that can be played offline try and update in Game mode which then refuse to work. Even games I have added outside of Steam that work just fine no longer work offline. I get a failed to launch error from Steam. Yuzu even refuses to work offline as it just gives me an error when I try any game that works just fine with internet.
The only way I can sort of play games offline is with Lutris in Desktop mode as some of the games work there. But the moment I go to Game Mode nothing will launch in offline mode.

[Prime Rib]

Just like the Steam Controller the Decks full controls won't work without the client open that includes using trackpads on Desktop mode and it's been a controversial topic since it was discovered. When it comes to your problems with Offline mode I personally haven't had a lot of moments using the Deck away from internet but I do know some PC games even single player ones are heavily DRM dependant on Steam so offline mode just cannot happen for some games. I'm surprised you've found Offline mode to be this problematic since the device was designed to play outside of the home and all I've seen are videos and pictures of people using it in out door area like parks, beaches.

[itchiebutt]

Well, I have tried cracked games as well which have 0 drm and they still refuse to run offline. I just get a failed to launch error in Desktop mode. When try and play them in game mode nothing happens.

[Marlock]

That's probably because you have to explicitly set steam app to offline mode itself before using those things without steam complaining of lack of internet... and because Valve isn't strongly motivated to test how well things work without Steam running... and because some software developers live/work in areas with very reliable internet (fiber, 5G, dense wifi hotspot coverage, etc) so they don't even think about "what if internet goes down?"

[itchiebutt]

I can load up the Steam Deck with it being online then disconnect the internet and it has issues. So, it doesn't matter for me anyway if I force offline mode, have no internet, or dis-connect after connecting to the internet.
The only time Offline works for me is if I played a game when I was online then close out of the game and turn offline on then it still works. But the moment I reset my Deck and don't go online, or dis-connect from being online nothing wants to work.

[nicoper]

FYI: You can always move the mouse cursor by holding down the Steam button and using the right trackpad, with the left/right triggers acting as R/L mouse buttons respectively.
Should at the very least let you start Steam in offline mode so it loads up your desktop config.

[American LoCOmotive]

You need to click "Start Steam in Offline Mode" instead of ignoring and closing it, then it will work fine in desktop mod without internet.

[Tadango]

I used my a week on vacation with mostly no internet, worked just fine :)