For performance in particular there isn’t something specific to the G2, other than using OpenXR.
The vorpX VR app does not take up significantly more GPU compared to the Rift S for example. With no background or with Ambience mode it seems to be around 25% of the GPU on a 1080ti. I don’t remember the exact percentage when using the Rift S but it’s no more than 10% difference.
The bigger resource hog will be the game’s resolution. On the Rift S there wasn’t much visual improvement above 1080p (in cinema mode), but the G2 at 1080p feels like crap so you need at least 1440p. Depending on the game you’re looking at 30-40% more GPU needed to keep the same frame rate at 1440p compared to 1080p.
One of the obvious things would be to use Z3D instead of G3D for games where it’s available and looks decent. Other than that maybe disable some post-processing that might not add much in VR like motion blur, depth of field and film grain. I also find anti-aliasing to be less of an issue in VR, definitely disable things like MSAA, but TAA, FXAA should be ok. Maybe lower model details if possible, these should also be less evident in VR as long as the textures are ok.