Never saw any ambient occlusion effect with MSAA. I bet it is unintentional.
I just settle with FSR2 and 0.5 scale since the game doesn't have that much texel density or world complexity to begin with. Though I have a UHD 240Hz monitor and therefore the game blasts at least 240 FPS which is just overkill for this game. Built in Vsync in 1/2, 1/3 etc would be great to address that...