Thanks to the generous help of Steam user "HamOnRye", we were able to get SteamDeck support working again!
Note that SteamDeck runs the Windows version of the game under its "Proton" compatibility layer, and this means the app thinks it is in Windows and makes native Windows calls, but Proton sometimes can't convert them to the SteamDeck Linux version. In the case of SpaceCorp, the cause of the SteamDeck crashing was the introduction of some native device detection services to deal with some app crashes on old iPhones (shortly after release). We were checking for RAM to help scale down graphics size, and this introduced a hardware call that Proton couldn't handle. We apologize for this. But thanks to HamOnRye, we identified and skipped this call for Window/SteamDeck.
Additionally, another one of the Proton limitations right now is sound support. For SpaceCorp, that means there is no sound on the SteamDeck. For now, we are going to just be happy we got SteamDeck working again, and we will research sound support to see if there is much we can do with the engine we are using. Cheers from outer space.