I had the same problem, after downloading and installing the 2 patches below, the setting appear, so try to update it to v1.2.0.11 version

It's a TENOKE release so it's a Steam version. It contains the game and the DLC. Since the DLC requires the base game to play, IGG always uploads both. Stand alone DLC that is playable MAY be uploaded separately but I have never seen it happen here.
Steam lists this version as 1.2.0.0 in the Dev Log.

This my friend is proper Fallout 2 sequel :)