Squat is a function of the square of the speed so at 4 MPH , squat will be minimal.
The only way your steering will be effected is by shallow water effect which has nothing to do with speed hence not squat.
Squat, a very misunderstood and while quite real, effect.
Squat, perversely sucks down your vessel to a deeper draft when you navigate in shallow water.
Shallow water effect interferes with the flow of water around the rudder and happens regardless of speed.
I can explain more but it is rather complicated π³
Bank effect caused by narrow rivers is something quite different although the hydrodynamic causes are very similar.