For a bit more performance change distribution exponent to 4 or 1 and see how it affects the FPS but dont expect too much, also keep an eye on Dynamic shadow distance as its value should be not be high and as for the rest of it i think you should balance it between Dynamic and Static shadows to get the best performance.
and for the softness of the shadows i think it depends on your scene’s lighting but I’m not quite sure about it.
also try modulated shadows (the one you are using now is CSM or Cascaded Shadows) and see if you get better FPS but keep in mind that modulated shadows have their own problems.