Distance Field Shadows on Large Objects

I have a hunch this is just a limitation of Distance Field Shadows, but couldn’t find a definitive answer. I’m working a game that utilizes both human scale meshes and mega-structures.

Is this a case where I need to rely on CSM only or CSM + Baked Lightmaps?

In the example below, distance field shadows work for the default cube/sphere up to a certain scale, then just quit working altogether.