I did notice a performance boost with FSR enabled but it was blurry using Balance. It wasn't obstructive enough to prevent me from seeing opponents I scoped on. Using performance did that actually. However, I never tried Ultra/high settings. So I cannot comment on that. Performance with balance gave me the same performance without it in Cold War. 1440p/1080p
I saw ~ 30 fps uplift on average by using Ultra quality. I did not notice any quality degradation but I did use sharpening from radeon software.