https://wccftech.com/grand-theft-auto-the-trilogy-the-definitive-edition-unfinished-vr-mode/

Grand Theft Auto: The Trilogy – The Definitive Edition features an unfinished VR mode that seems to work quite well even its current state.

As reported by Ben Turpin on Twitter, this VR mode is activated via a debug Unreal command and works pretty well as a first-person mode while traversing the world, far less in combat.