Serious Decky issues are rare. Usually when decky breaks, it just disappears from the deck until you manually reinstall/update it.

More rarely, a plugin will break steamOS. This gives a “Steam/Decky” has encountered a problem screen, with buttons to check for a decky update, disable Decky until next reboot, or uninstall the plugin that caused the crash. This is more serious, but is still extremely easy for users to deal with and get back to a working device.

I can’t remember if there was ever a point where Decky broke worse than that, but generally it’s pretty safe, especially if you’re on stable SteamOS.