Excellent. I can verify that sketch works as expected with my Nano and display.
You can try using a small screwdriver to adjust the contrast control potentiometer:
This can be in a position where the contrast is so low that the text is not at all visible on the display and it is only a solid blue color.
It is possible to configure the PCF8574 I2C module to use a different address by adding solder bridges to the pads here:
However, your module is in the default configuration so the address is 0x27.