Question about the slew rate
The large swing slew Rate is always limited by drive current limit and load capacitance which near 0 ESR compare to load R.


Thus dV/dt = Ic/C. Where Ic=V/R where for FETs, R = RdsOn or Ron and for BJT drivers , Ic is an active current limiter with the bulk Rce added to it.


  Where f(-3dB)=0.35/Tr , and Tr= 10~90% rise time, this is always less than the small signal f-3dB .


Closed loop gain is limited by small internal capacitance and feedback ratio where more -ve feedback results in lower output impedance. Thus more feedback with lower Zout and lower forward gain.   Acl*f = GBW.

In other words, for small signals, the Negative feedback (NFB) always reduces the output impedance for small signals which enables mor BW, but for large sig. the slew rate is limited by charge current Ic(max)=dV/dt= V/(R’C’) as the driver becomes saturated and cannot drive any more current to match the input risetime.

BJT OA’ s may have active current limiting of 30mA and slew rate is thus is defined for a fixed load like 30~100pF while FET drivers have Ron limits.  Since the cap ESR is lower than the load R, this if often the limiting factor. But then FET’s with lower Ron also higher Coss, so max slew rate includes other variables of the FET &amp; Load pF.