Alternative:
A little bit back in time, I liked to set up a “Light Dome” with MoGraph. This can be done roughly with a few clones or as in the example with a lot. The scene (attached) needs an HDRI, or an well exposed integer image. The overall illumination can be adjusted inside of that single light source [child]. Yes the scene attached is heavy, no doubt, but I would go higher, so adjust with a new sphere things to your needs, if that makes sense to you at all.
One way to accelerate this would be to limit values below 5% in the image, or make the Cloner Editable and let XPresso do it, switching off lights below a certain value, there is so much possible. BTW, no GI needed)
It produce a noise free shadow pass right into the Multi-Pass. Switch off Specular in the light source!
If you use Soft Shadow Maps, and find a good balance for your scene, then the first rendering can be stored if only the camera moves.
If you have a strong sun or other heavy light sources in the HDR, you might add individual lights as well, which can improve the overall scene perhaps.
As always, if possible I suggest to use your own HDRI, as you know then that they have exact values, e.g., if done well. Have a look at the link in my signature for tutorials about this. The material is based on over a decade of taking HDRI and over three decades shooting with [D]SLRs, etc.
