The grey hue over the 3D model

Question

I've been trying to render these models in a VisionOS app using RealityKit's Model3D API. The heart seem to appear dark all the time. Any thoughts on why this would happen? The idea is to show this model next to the text in the passthrough window. But that tend to render in this dark looking style. But the previews on the Xcode renders it nicely.

        Color.clear
            .overlay {
                Model3D(named: modelName, bundle: realityKitContentBundle) { model in
                    model.resizable()
                        .scaledToFit()
                        .rotation3DEffect(
                            Rotation3D(
                                eulerAngles: .init(angles: orientation, order: .xyz)
                            )
                        )
                        .frame(depth: modelDepth)
                        .offset(z: -modelDepth / 2)
                        .accessibilitySortPriority(1)
                } placeholder: {
                    ProgressView()
                        .offset(z: -modelDepth * 0.75)
                }
            }
            .dragRotation(yawLimit: .degrees(120), pitchLimit: .degrees(20))
            .offset(z: modelDepth)