Putting the following at the end of the starting script should enable pressure advance:
For Klipper:
SET_PRESSURE_ADVANCE ADVANCE=0.04
For Marlin:
M900 K0.04 ; Marlin V1.5
I've put 0.04 as the default, but would recommend using this tool (
https://ellis3dp.com/Pressure_Linear_Advance_Tool/) to find the optimal pressure advance constant (K) for your printer.