VR mobile resolution

How to increase the render resolution on VR headset?

I’m posting this question/answer because I’ve come to realize that it is harder and harder to find answers to questions these days. I think it is because of AI so I’m posting this.

UE in VR defaults to a certain resolution to save performance. If you need the quality you need to calculate the multiplier and set it yourself.

GEngine->XRSystem->GetHMDDevice()->GetIdealRenderTargetSize()

On Pico 4 it returns 1504x1504.
But Pico 4 has 2160x2160 native resolution.
2160 / 1504 = ~1.43

IConsoleManager::Get().FindConsoleVariable(TEXT("vr.pixeldensity"))->Set(1.43);