Check the Engine\Binaries\ThirdParty\Steamworks folder for a steam_emu.ini file. Ensure the DLC IDs are listed there.
You will need approximately 20 GB of available space for the installed game.
Select an installation path that does not contain special characters or spaces if possible (e.g., C:\Games\SoulCaliburVI ).
The repack usually includes a "NoDVD" or "Online Fix" folder (often using a ).