Unfortunately, the tools I need to port Stratus over to 4.0+ haven't been made yet. The Blender dev team do have plans to build them, but I have no idea when that'll be.

A dedicated GPU is highly recommended. Stratus can run on integrated graphics cards, but from my own experience, it's very slow.

Since Stratus is dependent on a part of the Blender API that has been deprecated, it may or may not work with macOS. I cannot, at this point in time, recommend Stratus for macOS until Blender is updated with the right tools.

Yes! Stratus just create HDRIs, so it works with both rendering engines.