The Sims 4 won't launch on Steam Deck. NO MODS/CCs

5f9092eef2bd0dcf​  Sorry, I was looking at two threads at once and got my wires crossed.  Options.ini has a fullscreen setting, which you can set to 0 (zero), or you can add -w to the launch options box to force the game to open in windowed mode.  Since we're on the subject though, try -dx9 to force DirectX 9 mode since DX11 isn't working.