Hiding the Scene Mesh for AR

I feel like I've tried everything, but I cannot get my AR project to load a scene without overlaying a giant box mesh over everything. I.e. I'm looking to be able to raycast against walls, but have it look as though you're interacting with the actual walls of the room via the Quest 3 camera. I stole the setup from the MRUK Sample:

I've tried messing with the Material for the GenerateProceduralSceneMesh call. I've tried asking the Room for the GlobalMeshAnchor and setting the actor hidden. I found a tutorial that recommended adding an OculusXRSceneActor to your scene and changing the static mesh class types based on anchor type - it didn't seem to do anything and apparently this class is now deprecated. Same thing with adding an OculusXRSceneGlobalMesh component and messing with the Visible toggle and the Material field - also deprecated. No matter how I mess with the materials or actor visibility it always looks like this:

I'm able to use MRUKSubsystem->Raycast to interact with the walls. I just don't want to see them. What's the accepted way to hide them?