RT shadows in the skylight help, but have a higher performance cost than RTAO.
I was forced to turn off RTAO though because it was creating a lot of noise in some objects that are seen close to the camera, ugly noise and even with high samples still happened badly (and got slower), and it actually replaces the occlusion from the SSGI, if you turn RTAO on with intensity 0 all the occlusion is gone from the scene, so it doesn’t clash with SSGi, just complements it.
But, unfortunately, isnt good enough.
Now, I know more or less how its supposed to look because I can bake it and see the areas that should be dark, for example, inside windows and balconies, but SSGI alone is not doing it.
In any case Im happy enough with the result to call it a win over DFAO/IS, not having to bake the scene is a plus, also not having the weird annoying flickering tiles from DF is a big plus.
Im also using some trickery to add AO per shader on trees, that helps a lot as well.