How to control HDRI Background + GI independently?

I would like to use an HDRI map for the background environment.

I figured how I can use the BP_Light Studio and using an HDRI map.

This HDRI map will be projected for the Background in my Scene Editor.
And at the same time, it’s going to be used for the GI.

I would like to control the GI Intensity independently.
And I also want to control the HDRI Map, that is going to be projected on a sphere in my level environment independently.

That gives me the option to change brightness, contrast, gamma, etc. as needed.

Question:

  • How can I do this?
  • How can I use an HDRI Map in as my background separated from my GI, Reflections, and Refractions (Evironment)?

Thank you so much for any hint!