If you were developing on the VIVE WAVE - All-in-One, you will need to pay attention to the following items when porting your project to the VIVE OpenXR - All-in-One.
Understanding Pose Origins
Floor: To get the pose corresponding to the floor plane, use the following settings:
Wave Plugin: Set the WVR_PoseOriginModel function parameter to WVR_PoseOriginModel_OriginOnGround.
OpenXR Plugin: [...]