So I guess using the data proxy makes the rust binary very light? So it’s also a win for classic lambdas?

The new runtime is around 230KB (already minified), and we now have string compression for the generated DMMF (from eg. 500KB uncompressed down to 60KB). Comparatively, the client runtime was previously about 2MB (excluding binaries), and the generated DMMF could also wildly explode. So that's a win for cold starts of regular lambdas.