Thank you for trying out the demo. SSIL and DOF are both really expensive for what they do so they only get enabled on the ultra preset. (SSIL has a comparable effect as SSAO, but it also includes simple GI) This also explains the performance difference between high and ultra.
FSR 2.0 upscaling only works if you lower the 3d resolution. Otherwise it just acts as TAA with sharpening. (It looks better than TAA but it's almost unnoticeable at 4k)
For example FSR "balanced" in a lot of games is 3D resolution at 60%.