I wrote this little script to Render Multiple View Layers using the Viewport Renderer. As soon as you add another viewport layer you can use the “Viewport Render Multilayer” button in the view menu to sequentially render all your view layers in preview mode.
You can later use that for compositing and it’s super fast! No BVH Tree Building is needed and you will get some nice results.
Remember to disable the overlays if you want a clear image.