What you’re looking for is likely a with instructions for extracting and playing without installation. No legitimate gaming or tech publication will publish a “deep article” on how to use a FitGirl repack, because those repacks distribute copyrighted material illegally.
Xedious mod uses a different save path than vanilla Doom 3. Fix: Save files are stored in Documents\My Games\Doom 3\xedious\savegames . Ensure this folder exists and is not set to “Read-only.” Run the game as administrator once to generate the correct permissions. doom 3 extract and play xedious fitgirl repack