Simple statement, without pressure there would be neither velocity nor recoil.
However the thing often misunderstood is Neither is directly related to "MAX" chamber pressure.
Bottom line is recoil is determined by total ejecta weigh & the velocity it is given, but the velocity of that weight is determined by the Total pressure curve pushing it. Thus both velocity & recoil are controlled by pressure, just not the Max pressure but total pressure.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra