For better image quality you have to raise the game’s resolution not the Oculus resolution. For FullVR games a 4:3 resolution like 1920×1440 is a good choice. If your PC does not support this resolution, check the Custom Resolution section in the vorpX help. It contains a step-by-step guide regarding adding custom resolutions.
FOV is handled by adjusting some values in the game’s ini files. If that fails, please check whether you maybe have forbidden apps to access your documents folder (e.g. in the Windows options). The game stores its .ini files below the documents folder.
Decoupling the camera from the walking direction is out of vorpX’s scope. That’s something that has to be supported by a game, one (rare) example would be Arma III with TrackIR tracking.