To completely solve the 1st problem, in my opinion, the best solution would be “don’t use any AO”
Yes, this is true. I never use AO as a universal render component or compositing pass. As Spikey said it’s inherently unrealistic, especially when Cycles delivers physically based Global Illumination. AO is only one part of the GI equation but.
I only use AO as a utility in textures / shaders. For example, I like to use it as a mask to populate crevices of an object with dust/grime.
