Turns out it isn't supported in PolySpatial yet: Unity Docs

Found a place to Upvote this in Unity's roadmap: https://portal.productboard.com/unity/77-unity-visionos-roadmap/tabs/272-mr-immersive-features under "Improved Graphics Support".

I tried all of these steps. Even when my MacBook is displaying to the VisionPro. just ran software updates on both and that seems to have worked