Game won't launch unless I'm in "online mode", but I'm on the internet

[Snoozy]

It's one specific game (Path of the Goddess) that I bought about a week ago and have launched multiple times, I have a few hours in it by now. I will come clean that there have been issues the whole time, it kept saying it couldn't sync with the cloud when I launched it. But I thought oh well, I only play on Deck so I don't care if it syncs with my account because I won't need the save file on any other device. A back-up save file would be nice, but I've never needed it before. Crucially, it let me play the game after these messages.

Until today. Now it says I need to launch the game the first time in online mode, and then closes. Well... not only is this not the first launch of the game, but I am online. I'm connected to wi-fi, it works perfect on all other devices, I can load the steam store, I can launch other games. I've tried rebooting, I've tried checking for updates, there's nothing plugged in to the Steam Deck, nothing else has changed about the device in the last week (I haven't messed with any files, changed anything about my account, etc).

Anyone have an idea of what might be causing this problem?