Want to use the op amp to set up a constant current source with output current of 4-5A, the power supply of the op amp can be ± 12V or 5V. Is there any recommended circuit
It seems to me that your requirements has error
shunt resistor 5 Ω
15 A current will create 75 V drop voltage at this shunt, this is unacceptable large value.
load: Resistive load 1-2.5 ohms
That you mean? If I understand it correctly, this is resistor between battery and power transistor? What function do you want to assign to this resistor?