Currently, the only way I can think of to speed this up would be to store the mesh (and texture) data in RenderTextures (using floating point textures for the mesh data), and use a shader graph with a vertex stage to read the vertex data from the texture when drawing. That’s basically how we support bake-to-texture particles.
However, visionOS 2 has added new low-level APIs (LowLevelMesh and LowLevelTexture) that we should be able to use in the future to speed up the transfer of mesh and texture data, and doing so is definitely on our road map. Right now, we transfer RenderTextures via a GPU blit (using the older, visionOS 1.0 DrawableQueue API), and with LowLevelMesh/LowLevelTexture, we should be able to do the same for any mesh/texture that’s loaded into the GPU on the Unity side.
Assuming this optimization would be particularly useful in your case, I’d suggest submitting it to our road map so that we can track interest and prioritize it.