Realistic VR Game Demo Build

I already have a full written script and I now need it translated into a short, visually playable demo as quickly as possible. The experience must feel virtually realistic, with high-fidelity graphics, believable interactions, and smooth user flow that matches every beat of the script... (Budget: $250 - $750 CAD, Jobs: 3D Game Art, 3D Modelling, C# Programming, C++ Programming, Game Development, Unity 3D, Unreal Engine, Virtual Reality)