Hi, Totoro, and thanks for your help!
These days I've done some tests, including the correction of the parameters that you have shown me, but without solving the problem.
double vRef = 1.079; // Volts
double Vin_LO = 4980; // milliVolts
uint16_t Rs_LO = 99.8; // Ohms
All values ??measured with a €40 multimeter (what I have)
Considered that your ESR Meter works, surely my problem isn't in the code.
I think there is a lot of work waiting for me...
Thank you again.