Teams Premium license needed for VR immersive spaces if not using custom spaces?

We're evaluating using Mesh immersive spaces - we don't currently need custom spaces yet. We already have access to immersive spaces through the Teams app using the pre-built spaces - do we need the premium license to join these spaces in VR if we're not doing custom spaces or are we limited to 2D only without Teams Premium? It appears to currently be blocked via the Mesh app, but documentation is sparse - maybe some other configuration is blocking it?