hello
I am looking for an easy sensor that could help me to measure the pressure drop of liquid flow with a micropython or Arduino (as it would be quiet the same wouldn't be?)
you need to first determine the differential pressure.
typically it will be from the data sheet of your primary element (the thing in the pipe)
an orfice plate is one such primary element.
the flow rate and the opening, along with the inlet and outlet pressures are usually the starting point
and the device should have a table, chart, curves or calculations.
the sensor must be designed for use with the fluid you want to use.
I submit that you may have posted an X/Y problem
you have ruled out easier devices and are only asking about a very specifc technology.
fluid flow can be accurately measured with either a turbine or paddle wheel sensor for lots less cost than a differential pressure sensor.
second, the output is not linear, the fundamental formula is expressed with a square root.
If your requirement is by means of an orifice plate or an AMSE nozzle, then delta-P is required.
if you just want to know the flow, there may be simpler means.