The newly updated code is shown at post #21.
GPIO:
pcnt_config.pulse_gpio_num = GPIO_NUM_14;
It's really complicated for me print data to serial, because my flow meter is already mounted, and my PC is not near it. Basically I am testing whether it connects to Wi-Fi without my sensor attached.
P.S: at your post #45 schematic Then works indeed, I've just checked it.